Though these parameters are not allowed in the server parameters blade, there is a workaround you can use to set below parameter through init_connect.
For example:
• Go to Azure Portal, then locate your Azure Database for MySQL
• Under the settings section, click Server Parameter to open the server parameter page
• Search for “init_connect”
• Put the parameters in the format: SET parameter_name=YOUR_DESIRED_VALUE in value column.
Example for setting multiple parameters: init_connect= SET character_set_client=utf8;SET character_set_database=utf8mb4;SET character_set_connection=latin1;SET character_set_results=latin1
• Click Save
NOTE: Please note that init_connect is executed for each client that connects to the server and it is at a connection level.
You can check the value of these parameter after above steps using below commend:
show variables like 'character_set%';