How to change wording in Thank you page?

AFTER USE THE FORM BY A CUSTOMER, IS IT POSSIBLE CHANGE THE WORDS IN "GRAZIE PER IL SUO PAGAMENTO"?

I'm assuming that you are referring to Thank you page:

You can change it by going to Thank you Page option in your form builder:

And edit that page there:

Hope it helps.

Let us know please if we can assist you more.

Thank you!