Sharepoint bibliothek questions from a neewbie (PowerApp formula)

Dear all,

I'm very sorry for my absolute beginner questions. I try to create a form for our document management. But I'm still not able to change the field for the "name" of the document as a fillable field.

Could you please help me? 

In addition is there any solution that the users have to fill the form in advance either if they use a template or upload it's own document in the sharepoint bibliothek?

Please don't hesitate to ask me if my questions are not clear.

Thank you very much 🙂