You can do a lot while on a call in Teams
Place a call on hold
Select More actions in your call window and choose Hold. Everyone in the call will be notified that they've been put on hold, and you can continue your call by clicking Resume.
Transfer a call
Select More actions > Transfer in your call controls. Then, type the name of the person you want to transfer the call to and select them. To finish, select Transfer.
Consult then transfer
If you want to check in with someone before you transfer a call to them, select More actions > Consult then transfer.
Under Choose a person to consult, start typing the name of the person you want to reach and select them when they appear. You can call them, or consult with them over chat. When you're ready, select Transfer.
Add a delegate
You can pick someone in Teams to be your delegate to receive and make calls on your behalf. When you add a delegate, you’re essentially sharing your phone line with them, so they can see and share all of your calls.
To designate a delegate, select Settings and more next to your profile picture at the top of Teams and choose Settings > General. Under Delegation, select Manage delegates. There you can see who you're a delegate for, and add and remove your own delegates.