onedrive

Hi Team, I am asking for a tax advisor firm. They have a server license for microsoft and desktop licenses.

What they want is to share documants safely with their customers (receipts, tax declaration etc.)

1) how can the creat a solution that each customer has his own secure folder to share documents?

2) is it possible that they get a mail/info notice, if a customer added a document?

3) if they do not have 365 but a desktop and sever license, what license is required to use this options

4) As the customers are external, does the external customer who adds a document also have to have a license?




Thanks


Claudia