Hi, @Surbhi Sharma Welcome to Microsoft Q&A thanks for posting your question
When I try on my side, I am able to see the Migration extension when I connect to SQL Server on prem, but not when I am connected to Azure SQL DB
Below is the supported source and Target
https://learn.microsoft.com/en-us/azure/dms/resource-scenario-status#supported-migration-scenarios
The server that you right-clicked, and clicked manage. Is that your Source (what you are trying to migrate) or your Target (where you are trying to migrate to)?
Regards
Geetha