Custom domain question

Hello, good morning, how are you, I would like to know if with the plus plan I can have the project domain completely customized with the name I choose?

Yes, the Plus plan includes an option to set your own custom domain.

On the plus plan, can I remove the shapespark name from the domain?

Yes, with the Plus plan if you have your own domain, say, you can change the <username> in scene URLs to <subdomain> (where <subdomain> is the subdomain name chosen by you).