Wechseln zwischen mehreren Teams-Konten innerhalb von App oder Browser
<In English>
Hi ArturYU,
To know what email address associated with your account A:
- Go to the Teams app > Navigate to Team, click on ... three-dot button next to team name >
- Click on "Manage Team" > Members
- Hover your cursor on your name > You'll see a pop-up window with your email address details
Please be advised, to see both account A and account B associated teams, please make sure that your both account at least member permission on the Team.
https://support.microsoft.com/de-de/office/hinz...
You could also consider allowing member access to Account A in a free organization associated with account B.
https://support.microsoft.com/de-de/office/verw...
Regards
Nik