My initial details then more to help
In your case you are in CopilotStudio.microsoft.com and are trying to Share It I believe, based on the details I am seeing. This requires that you talk to the Tenant Admin to go into M365 or Power Platform admin settings for group policies, to see which area the Tenant has it blocked, and then they have to change the DLP or other Policy they created to enable you to Share it That is the admin they mean.
So there are differences because you can do the following
1. Create and share an organization agent in the M365 UI (for chat)
2. You can create Agents that you embed in other uis, like Power Platform or a WebSite
3. You can create Agents that are in Teams only for instance
4. You can create them for embedding in things like Slack etc.
Without seeing more details, it could be referring to either the Teams Admin or the M365 Admin Screens. In each location you can find apps, depending on the Channel you are deploying too or Sharing.
So if you were in Copilotstudio.microsoft.com and built one there you can deploy it to many different channels and then it depends on your Tenant Admin configurations whether or not your Admin (m365/Teams) has to step in to actually Approve the Share/Publish
Then there is if you are in CopilotStudio.microsoft.com and you pick the Copilot for M365 Agent that exists and INSIDE of that, build an agent for M365, its like a wrapper, that sits inside of CopilotStudio, but is actually instead for M365 as an Organizational level Agent, versus when you create one there for yourself.
Again when you share that, depending on the Tenant Permissions, it will either allow you to share it, and then people can see it/add it in M365 and or Teams, OR it will tell you that an Admin must approve and complete the process.
If these suggestions help resolve your issue, Please consider Marking the answer as such and also maybe a like.
Thank you!
Sincerely, Michael Gernaey