I have previously configured Shared mailbox in Microsoft 365 admin center & sent an email using Power Automate successfully.
Follow below steps to create a new Shared mailbox & grant necessary permissions:
Create a shared mailbox from Microsoft 365 admin center or Exchange admin center
Grant below permissions to ...
If your invoices are of a consistent format (formatting of the invoice is the same), take a look at SharePoint Syntex which can extract the contents of say the company invoiced, amount, and so forth and add it to a Document Library column.
You would still need to take the emailed invoices and use Power Automate to place it in the proper library, of course.
There is a print option in Powerapps use the function Print() you can also hide/show buttons when you print using the "form.Printing"or not(Form.Printing) in the visible property. however it can only print what is on screen in a single page. If it is is multiple pages you are out of luck and need to use ms flow instead.