Hi Swathi,
You can find it in the general settings menu in your projects page in Mendix Developer Portal. It is called App ID. You can also find detailed info in the following link:
https://docs.mendix.com/developerportal/collaborate/general-settings
This is part of the Teamcenter SSO configuration
If you aren’t using Teamcenter SSO, then you leave this blank
If you are using it, then the IDs are in the SSO config