Building, integrating, or customizing apps and workflows within Microsoft Teams using developer tools and APIs
Hi Marilet D,
As you post your questions in the Microsoft Teams category, may I confirm if you mean to add and use third party APP to Microsoft Teams?
If so, your administrator need to firstly enable the ability to add third party APPs for your account or for your tenant in the Microsoft Teams admin center. For more detailed instructions, please see: Manage app permission policies in Microsoft Teams
After the admin enabled this ability for you, we can refer to this article to add it to Teams. Please kindly note, we can only add third party APPs that can be found in the AppSource.
However, as the APP “classdojo” is not available in the APPSource, it means this APP hasn't integrated with Microsoft Teams. Given this situation, you may need to confirm with the APP support team as well. Thanks for your understanding.
Best regards,
Jennifer