Missing Microsoft Partner (4990cffe-04e8-4e8b-808a-1175604b879f) API permission

JillArmourMicrosoft and yashubale ,

Are you trying to add under "Enterprise applications" or "App registrations"? The linked document is about App registrations. 

I can find it just fine, from my AAD/Entra CSP Partner Tenancy:

OR:

That is from going to App registrations and selecting an existing App of mine (if you can't find it when creating a NEW App, try adding the app without permissions and then go back and add them later: find the App, go to Manage, API permissions, and then "Add a permission" and "APIs my organization uses"). I tried both: "Microsoft Dev" and "4990cffe-04e8-4e8b-808a-1175604b879f" (the whole ID) to find it.

I CAN find it under Enterprise Apps, but I don't think that's where the article is directing you (but I had to search by the whole app ID) :

If you're trying all that and STILL CAN'T find it... I don't know.... Is your Tenant linked to an MS Partner Center account? 

When I go to one of my CUSTOMER'S Tenants and search for that App ID and create an App registration I CAN find it, but it has a DIFFERENT NAME:

And if I search for Microsoft Dev I CAN'T find it:

So my guess is that if you can't find it at all there's something not set correctly in or for your Tenant that allows it to be added (for whatever reason). The App ID isn't listed on the normal list of Well Known MS Apps, so maybe it's specific to Partners?
https://learn.microsoft.com/en-us/troubleshoot/azure/entra/entra-id/governance/verify-first-party-apps-sign-in

There aren't a lot of hits when I Google for it (even using Bing), so it's obviously niche. But it is certainly MS Partner related. 

If you go to https://partner.microsoft.com and log in with an AAD/Entra account from the tenant you are trying to add that App ID to an App Registration IN ... is that your MS Partner Account? If you go to top-right Gear, Account Settings, Organization Profile, Identifier does it list your Associated Partner ID on the CSP tab? Under Tenants does it list your Microsoft Entra tenant ID?

If not, then try with your MS Partner Tenant. If it does... you'll probably need to contact your MS Partner rep and have them check things.

If it helps I did this from my Canadian Partner Tenant. When I tried my US Partner Tenant I had the same experience as from a CUSTOMER tenant ... BUT I don't have the same admin permissions in our US tenant... so maybe it is a PERMISSION issue? Do you have Global Admin?

Hopefully some of that is useful, if not I'm afraid you'll need to contact your MS Partner support person.

   --Saul