Does any one have idea how to assign Teams addon license to a user if we have both T3 and Teams addon

Teams migration is included in the On Demand Migration T3 license.
Are you referring to the Teams Chat Add-on, which makes Chat migration faster (chat migration is included in the standard T3 license, only it is very slow)? 
For this, there is a check box when creating a Teams Chat migration task:

Teams migration is included in the On Demand Migration T3 license.
Are you referring to the Teams Chat Add-on, which makes Chat migration faster (chat migration is included in the standard T3 license, only it is very slow)? 
For this, there is a check box when creating a Teams Chat migration task: