I am not sure when this became available but for Azure SQL Database 150 compatibility level is now available. Last time I created a database few weeks ago, only level 140 ( SQL Server 2017) was available so I think it is a recent thing.
Upon some testing, if you create a new Azure SQL Database by default it is 150 as per the screen shot below (from the script action command)
Via SSMS (SQL Server Management Studio) you can view the database properties, you will clearly see the new level.
What does this mean? Well I can start leveraging the new changes that SQL Server 2019 engine has to offer. I am thinking Intelligent query processing feature family such as Approximate count distinct etc.
Fun times ahead.