Permissions
Any user can create temporary objects in tempdb. Users can
access only their own objects, unless they receive additional
permissions. It's possible to revoke the connect permission to tempdb
to prevent a user from using tempdb. We don't recommend it because
some routine operations require the use of tempdb.
The tempdb system database is a global resource that's available to all users connected to the instance of SQL Server or connected to Azure SQL Database.
By default, server admin, database owner or a user with required permission can access the tables of tempdb.
This official article on tempdb database is related to Azure SQL Database. Please go thorugh for more details and better understanding.