If the invitation was send to your personal Microsoft-recognised account, provide your credentials in the follow screens
Then your password
If you have activated the multi-factor authentification for this personal account, another pop-up could appear asking for a 6 number digits provided by an app, send by SMS… it wil ldepend how you have setup your personal account.
If your password is correct, the first time it will ask you if you want to store your credentials
Click on “No” if your are on a shared computer or if you don’t want to store it.
After that you will have access to the site.
If you have a error message saying “You need permission to access this site“, 3 options:
The invitation to shared was send to another email adres
The invitation right was revoked
You try to access the site without being invited