Recently, it has become possible to add members to a team. It is also possible to send people a code to join a team. The big advantage is that you as a user have the choice to join. And that you are not automatically already in the team.
To generate the code, you must be the owner of the team. The code also only works for users in the same tenant, so external users cannot use the code.
How does this work?
In your team, go to the 3 dots behind the team name.

then click on manage team:

In Manage Team, go to settings:

And now click on team code.

Then click on generate.

The code that is generated can be restored, deleted, copied or even shown on the entire screen, easy if you are in a room when everyone in the team has to be. In my case for this demo I copy the code.
As a user you receive the code and you can choose whether you want to join this team. This is a difference with a normal membership invitation that you cannot decline.
Then you go to Join a team or create a team:

In the screen that follows you will see all your teams that are public and/or private, where the private team cannot be added by default. but you will also see right next to the button create new team. Become a member of a team here we paste the code that we generated earlier or the code that you received from the owner of the team.

After entering the code you will see the button appear to become a member:

We click on this and are automatically added to the team.

I think it is easy that you can choose whether or not you want to become a member of a team. This also immediately ensures a lot less pollution in the memberships of your teams. Have fun with this tip.