What you probably are seeing is the request to register your version with Microsoft, which is required within 30 days of first usage.
For this you need only some email-address of yours that can be used to create a Microsoft account. You even can register more than one installations with the same account.
You can check the status of your license via Help/About Visual Studio
when you click on check for an updated license you are asked for your Microsoft account.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…