Each team code is intended to make it easier to invite other users to join. Although teams can be searched by name, the listing can be confusing. This can cause a user to join a team by mistake.
By sharing the code, the user who receives it will only need to enter it into the search bar so that the only team listed is the one they want to join.
You will be able to find your team code within this section by selecting the About team option, and will have the possibility to copy the code from the copy button.