The sender domain (notificationmail.microsoft.com) is a genuine sender, however, scammers may spoof the senders address, so it is best to not click anything in the Email and delete it.
If that Email is indicating your OneDrive cloud storage is full, if you use Outlook Email, that may cause that notification.
Log into your OneDrive account on this link (https://onedrive.live.com/) and at the bottom left, check your OneDrive storage statistics, have you exceeded your storage allocation?