To me, the freelancer has sent a link on which I registered for the first transaction without commissions, the client sets the amount, he commits the commission.
How to solve this problem?
I do not have any idea what you are talking about.
Please answer the following questions if you want me to help you:
A) Are you a client or freelancer?
B) Do you have an Upwork contract in place?
C) What is the name of the website that the link is on?
Edited to add: Ah... I see that moderator Vladimir has understood the issues you are referring to far better than I did! There is no need to answer my questions as it appears he is on the right track.
If you used the correct sign up link the freelancer received and never used Upwork before as a client, your contract will qualify for having zero service fee applied to it. Note that the freelancer pays the fee and the information will be displayed on their end once you make an offer to them.