Adding members in Team Channel

Hi, I created a channel in team as Private type. Whether i can able to add only the Team members in the channel or anyone?
I try to add other members in channel those who are not in the team, but can’t able to add them in channel. Why?
Also tried with API is not working? Is there any way please response

All Microsoft Teams are backed by an Activity Directory group. To add/remove members you will need the Active Directory activity pack which is on the official feeds. You can find out more at