Firstly setup properly Azure DB firewall, then execute the following command within you Visual Studio,
Update-Database -Configuration {Project_Namespace}.Migrations.Configuration -Verbose -ConnectionString "Server=tcp:{Azure_SQL_Server}.database.windows.net,1433;Initial Catalog={Azure_DB_Name};Persist Security Info=True;User ID={Azure_DB_Username};Password={Azure_DB_Password};MultipleActiveResultSets=False;Encrypt=True;TrustServerCertificate=False;Connection Timeout=30;" -ConnectionProviderName "System.Data.SqlClient"