What is the best way to legalize if you have already conducted activities on Upwork?

Question

Upwork

Initially, I did not imagine that the income from Upwork could be any high. But, "flooded."
So the question is: how is it better to legalize if there was already income from clients?
As far as I understand, Upwork in the "Act of Acceptance" indicates the amount of the commission.
Some clients will switch to the 5% rate soon. If the tax authorities hypothetically want to check, then discrepancies in Upwork commissions will immediately show up.
Or score, and just keep the extra money in case of fines?
PS: I have never been an individual entrepreneur and personally had no business with the tax, so the questions may seem naive, sorry.
PPS: we are talking about Russian tax residency.

Answer 1

I don’t know where, in Ukraine everything is simple. Grandmas went to the account of the entrepreneur, he paid tax on them. Everything.
All other commissions and so on do not bother anyone at all, your income is what fell into your entrepreneur account.

Answer 2

it is better to legalize from the new year, you can say from scratch

Answer 3

You can pay income tax as a simple natural person.