Controlling settings, permissions, and membership within Teams and channels
Microsoft Teams does not support bulk-adding 100+ members directly from an Excel/CSV email list in the Teams client. Members must be added either:
- Manually in Teams, or
- By using Microsoft 365/Azure AD/PowerShell (not covered in the provided context).
From the available information, only the manual method in the Teams client is documented:
- Open Microsoft Teams (desktop).
- Go to the team where the users should be added.
- Next to the team name, select More options (three dots) > Add member.
- In the Add members box, start typing a name, distribution list, security group, or Microsoft 365 group, then select it from the results.
- External people can be added as guests by typing their email addresses one by one.
- When finished, select Add.
- Optionally change any member to an owner by selecting the down arrow next to Member.
To add 100+ users “at once” without manually entering each email, the documented approach is to first put those users into a distribution list, security group, or Microsoft 365 group (outside of Teams), then add that group to the team using the steps above.
References: