Thank you GlinetteC

 That is what I did with a short old project I had, just to try the "project" feature but the thing is, since the numbers of my invoices are not custom, by deleting the old one and creating a new one the invoice number changes and since I'm dealing with old invoices, that already has being sent to clients and already has being match with bank transactions, I believe that deleting and creating them again is going to be chaotic. I can find the time to do all the steps for each of the transactions made at least a month ago but if I have to replicate every invoice and payment and bank match paying attention to the invoice number and the date I think it's better to leave it like that and use the "project" feature for really new projects. What do you think?

PS. When I created the payment receipt of an invoice in this project I'm testing with, under the heading "received from" instead of the name and the address of the client it appears received from "project name"

Is there a way I can change that? Thank you very much for your help. I appreciate it.