If you need to install 365 for a client who has just bought it (now mostly they have no media) avoid the pain of waiting for a download install, especially while waiting around.
Get your own copy to use to install from.
On the 365 install page under Install options there is now (maybe was there before) an offline installer option.
Let’s you download 365 for later install.
Once on the page you can download both Business and home versions. (to save to use no matter which version was bought)
Then you can install 365 from your USB media, save hours if client has usual slow connection.
Once done it asks for your key and email account.
Cancel all these and it will say activate before …date… and then you can do this onsite with the client so they put THEIR MS email account and password in.