To transfer a call, select More options 
> 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.
Click the drop-down arrow in the Transfer button to see more transfer options. Choose Work to transfer the call to their Teams number, or Work voicemail to send it straight to their voicemail. If they've added any other phone numbers to their account, like their mobile number, you'll see those options in the list, too.
Just keep in mind you can only transfer calls when you're talking one-on-one.
Consult then transfer
Need to check in with another person before transferring a call to them? When you're in a call, select More options 
> Consult then transfer. Then, check in via chat or audio call.
