Hello Katecovill,
If you are the team owner, you can try to get the team generated code from the team's settings ( More options)> Manage team > Settings > Team code > Generated, after that it would prompt a team code, and you could share it with others to join the targted team, thanks. For more details, please refer to Create a link or a code for joining a team > Create a code.
Please feel free to let me know if you need any further helps, thanks.
Best Regards,
Oliver