An independent studio is a company, you must have it registered with the tax agency in your country and it must have its ID to pay taxes.
If you identify yourself as such, then when processing the tax interview, the tax ID must match the rest of the data, otherwise you will have problems when validating the data.
If you do not have any of these, then you are a natural person selling (the most common thing to find on Itch).
If you want to create a studio, it is best to consult with someone who knows the laws of your country, in order to avoid any legal problems.