You’ll usually need a few essential documents to register as self employed. Those include the proof of your identify or your passport or national ID card, and your address details. Additionally, you will be asked for information on your business activities, or, in certain cases, your national insurance number (UK residents) too. You may in addition to the required documents need to apply for other documents, for example, depending on your situation a business license or the registration on certain local authorities. Use your country’s tax authority to check exactly what is needed of you.
Suggested read:
https://accbytes.com/blog/register-as-self-employed/
