Jeffrey Verheul shows how to enable replication from your on-prem SQL Server up to Azure SQL DB:
Replication to another on-premise instance is easy. You just follow the steps in the wizard, it works out-of-the-box, and the chances of this process failing are small. With replicating data to an Azure SQL database it’s a bit more of a struggle. Just one single word took me a few HOURS of investigation and a lot of swearing…
The magic word is “secure.” Read the whole thing if you’re thinking of migrating an app to use Azure SQL DB and want to minimize downtime, or if you just want that extra level of protection that having a copy of your database out of the data center can give you.