Using Azure MSSQL "contained database" how do you force a user to reset their password?
This is currently not supported and you cannot use Must_Chance, Check_Policy or Check_expiration as of now.


  Keyword or statement option 'check_policy' is not supported in this
  version of SQL Server.


You can vote for this in the forum :

https://feedback.azure.com/forums/217321-sql-database/suggestions/10491111-azure-sql-database-password-force-change-on-first