Have you ever faced a scenario doing bacpac for a large database in order to move to another subscription, and waiting endlessly for this process to complete and thought why are't we able to just restore AzSQL Database. Well actually we can and it is well documented in Microsoft too under (Copy a transactionally consistent copy of a database in Azure SQL Database ) the problem is it is not under restore section so on basic google search it becomes bit tricky as the default bacpac option is the one you are going to see.
Summarising the process in the link, you can do this only using SSMS and not through Portal,You have to use a login that has the same name and password as the database owner of the source database on the source server. The login on the target server must also be a member of the
dbmanagerrole, or be the server administrator login. Then execyte the below TSQL(Server name will be just the AZSQL Server name without database.windows.net
-- Execute on the master database of the target server (server2) to start copying from Server1 to Server2
CREATE DATABASE Database2 AS COPY OF server1.Database1;
Hope the article helps!