If you have just started to be self-employed, one of the first doubts you probably have is how to make invoices as a freelancer.
What information do you have to include? How is VAT calculated? Do I have to apply personal income tax? How do I number them? Can you do them manually or do you need an invoicing program?
In this guide, we explain the fundamental aspects to start invoicing correctly and better organize the management of your activity.
Note: taxation may vary depending on the activity, operation and particular situation of each self-employed person. If you have any questions about VAT, Personal Income Tax or applicable exemptions, consult a tax advisor.
Is a self-employed person obliged to issue invoices?
In general, entrepreneurs and professionals must issue an invoice and keep a copy for the supplies of goods and services made during their activity. There are particularities and exceptions depending on the regime and the type of operation.
Therefore, learning how to issue and organize your invoices correctly is a fundamental part of managing as a freelancer.
What information should a self-employed invoice include?
According to the Tax Agency, an ordinary invoice must contain certain mandatory information. Among the main ones we find:
- Invoice number and, where applicable, series.
- Date of issue.
- Name and surnames or company name.
- NIF.
- Corresponding data of the recipient when required.
- Description of the products or services.
- Taxable base.
- Tax rate applied.
- Corresponding tax liability.
- Date of completion of the operation when different from the date of issue.
Depending on the type of transaction, additional mentions may be necessary, for example when there is a VAT exemption or reverse charge.
How to make an invoice as a freelancer step by step
Let’s look at a simple example.
1. Assign a number to the invoice
Invoices must follow a sequential numbering within each series.
For example:
2026-001
2026-002
2026-003
You shouldn’t randomly assign numbers to every new bill.
2. Enter your details
Correctly identify who is issuing the invoice.
Normally, data such as:
Name and surname / business name
NIF
Tax domicile
3. Add customer details
Include the recipient’s data that corresponds to the type of invoice and transaction.
If you regularly invoice other companies or professionals, having an up-to-date customer file will save you from having to enter the same information continuously.
4. Describe the product or service
The invoice should allow you to identify what you are charging.
For example:
Facial treatment service – 60 €
or:
Hairdressing service – Coloring – 45 €
Avoid excessively ambiguous descriptions when it is necessary to correctly identify the operation.
5. Calculate the taxable base
The taxable base is the amount on which the corresponding tax is calculated.
For example:
Service: 100 €
Taxable base: 100 €
From there, the corresponding taxes will be applied according to your activity and operation.
How is VAT calculated on an invoice?
When the transaction is subject to VAT, you must apply the corresponding rate.
Let us assume, just as an example, a transaction whose taxable base is €100 and to which a VAT of 21% corresponds:
Taxable base: 100 €
VAT (21%): 21 €
Total: 121 €
Not all activities or operations necessarily have the same tax treatment. That’s why you should check which VAT rate specifically corresponds to your activity.
When does a self-employed person’s invoice carry personal income tax?
This is another frequently asked question.
Personal income tax should not be automatically added to all invoices simply because you are self-employed.
The obligation to withhold and its percentage will depend, among other factors, on the type of activity and the recipient of the transaction.
Therefore, if you are not sure if your invoices should include personal income tax withholding, it is advisable to check your particular situation with your advice.
Simple example of a self-employed invoice
Let’s imagine a €100 transaction to which VAT corresponds to 21%, without entering into possible withholdings:
Invoice: 2026-025
Date: 05/10/2026
Concept: Professional Service
Taxable base: €100.00
VAT 21 %: 21,00 €
TOTAL: €121.00
To this content should be added the mandatory data of the corresponding issuer and recipient.
When should you issue an invoice?
The time frame depends on the recipient and the type of transaction.
For example, in general, when the recipient is not a businessman or professional, the invoice is issued when the transaction is carried out. When the recipient acts as a businessman or professional, there are cases in which it can be issued before the 16th day of the month following the accrual.
That is why it is advisable not to accumulate outstanding invoices and to keep billing up to date.
Do I have to keep the invoices?
Yes.
Entrepreneurs and professionals have retention obligations both on the invoices received and on the copies of the invoices issued. The regulations allow this obligation to be fulfilled by electronic means as long as the corresponding requirements are respected.
Good digital organization can avoid having documents spread across folders, emails, and different files.
Frequent mistakes when making invoices as a freelancer
When starting out, it is relatively easy to make mistakes such as:
- Forgetting to number invoices correctly.
- Entering incorrect customer data.
- Applying taxes without checking which ones correspond.
- Not correctly differentiating taxable base, taxes and total.
- Losing invoices issued.
- Have the information distributed among different documents.
- Leave all billing for the end of the quarter.
The higher the number of customers and transactions, the more complicated it is to manage everything manually.
Can I make my invoices in Word or Excel?
A template may seem sufficient when you issue very few invoices.
However, as the workload increases, several drawbacks appear:
- You have to enter data repeatedly.
- You must manually control the numbering.
- It is easier to make mistakes.
- Customer information is separated.
- Viewing history may be slower.
- Management becomes less efficient.
In addition, if you use a computer billing system, you must take into account the regulatory requirements that apply to it.
For this reason, for a stable professional activity it is usually more practical to use a specific program.
If this is your need, check out our guide on easy and affordable self-employed invoicing software.
This way we keep both intentions separate: this article explains how to make an invoice, while the previous one answers those who are looking for which program to use to invoice.
VERI*FACTU and the self-employed: what do you need to know?
Invoicing is undergoing an important process of digitalization.
The new requirements for computer billing systems affect how certain programs must generate and maintain billing records.
After the extension of the deadlines, the Tax Agency indicates that the other companies and self-employed workers affected that use computer invoicing systems must adapt before July 1, 2027.
There are two modalities provided for adapted systems:
VERI*FACTU: automatically sends billing records to the Tax Agency.
NO VERI*FACTU: does not carry out this automatic submission, but must comply with the requirements established to guarantee the integrity and inalterability of the records.
Therefore, if you are going to choose software to manage your activity, it is also advisable to consider its adaptation to invoicing regulations.
Billing and management: better if they are connected
If you’re a professional who works directly with clients, making invoices may be just a small part of your day-to-day management.
You also need to:
- Manage appointments.
- Organize clients.
- Control services.
- Make collections.
- Send reminders.
- Check your agenda.
- Manage products or stock.
Using different tools for each task can end up complicating the job.
With Wilapp you can centralize billing, clients, agenda and other management areas from the same platform.
In this way, this article maintains its informative objective on how to invoice as a freelancer, while the main page of Wilapp concentrates the commercial intention related to the complete management software.
If you work with appointments, also connect your billing with your agenda
This is especially interesting for self-employed people in hairdressing, aesthetics, barbering, physiotherapy, tattooing, wellness, and other sectors who work by appointment.
In these businesses, the process is connected:
Client → appointment → service → collection → invoicing.
Centralizing it avoids having to continuously duplicate information between different applications.
If your main problem is organizing reservations, you can learn more in our guide on how to organize appointments for your business.
Frequently asked questions about invoicing for freelancers
What do I need to make an invoice as a self-employed person?
You must include the corresponding mandatory data, such as numbering, date, identification, description of the operation, taxable base and applicable taxes.
Do all invoices carry VAT?
Not necessarily. The treatment of VAT depends on the activity and the operation carried out. There are exempt transactions and regimes with particularities.
Do all self-employed invoices carry personal income tax?
No. The application of withholdings depends on the type of activity and the operation. It should not be applied automatically for the simple fact of being self-employed.
Can I use a program to make my invoices?
Yes. In fact, using software can simplify the numbering, customer management and organization of invoices. If you use a computerized billing system, you must make sure that it complies with the legal requirements that apply to it.
What program can I use if I also manage clients and appointments?
If you’re working by appointment, a comprehensive solution can be more convenient than using multiple separate tools. Wilapp allows you to manage billing, clients, calendar, and other tasks from a single environment.
Conclusion: making invoices as a freelancer can be simpler
Learning how to make invoices as a freelancer is one of the first administrative tasks you must master when starting your activity.
Remember:
1. Number invoices correctly.
2. Include the required data.
3. Describe the service or product correctly.
4. Apply the taxes that correspond to your situation.
5. Keep your invoices organized and preserved.
6. Use tools that help you reduce manual tasks.
And if you also work with clients and appointments, centralizing billing with the rest of the management can save you even more time.
With Wilapp you can bring together invoicing, customers and agenda on the same platform to simplify the day-to-day running of your business.
