This means that TAP Studio actions that could be used to access these services (like Get Email Messages - IMAP) will no longer work. Fortunately, TAP now offers dedicated actions for 365 automations.
In order for TAP to authenticate against Microsoft 365 services, it requires an application to be added within the Azure Active Directory platform (for your tenant). Subsequent API permissions must the be added to this respective application, specific to your automation requirements (accessing user information, email automation, etc.). For detailed information on specific API permissions required, please check the dedicated Microsoft 365 Automation actions.
After adding this application within the Active Directory, users accounts will need to consent to it, acknowledging they accept to grant these permissions to the application. Please note that the application itself is an abstract entity and does not "run" effectively in the cloud but is rather used for storing permissions and metadata.