Entering professional expenses

Hmm, I would think carefully about putting that in your accounts :)

How are you going to prove that you purchased trade goods from that supplier? (in the event of a tax audit) You could have bought anything there, at least from most suppliers...

If you really want to include it, you could enter them as a supplier: private person. Then you will also have to include it in your expenses, but it seems like a borderline case to me. Unless you can obtain some additional information at the time of the tax audit to prove it, but otherwise...

I think there's an article from it in the learning center, something about 'what do you need...'

If you search for accounting, you'll find it.

It states that a bank transaction is possible, but only for things for which you can indeed provide additional documents from afterwards. Think of rent or similar.

Regards, Filip