software like microsoft whiteboard

I want a program like microsoft whiteboard. This program must run on the server and each user can create a whiteboard. Functionalities: you must be able to send invitations to other users, and both work on the same screen at the same time, the system writes the initials of the person who made the changes. have to give to paste a background image. you have to give the document to be saved and reopen it. https://www.microsoft.com/pt-pt/p/microsoft-whiteboard/9mspc6mp8fm4#activetab=pivot:overviewtab