Merge call doesn’t work
while iam calling someone I can add a call but when i try to merge the two calls by clicking merge call noting happens it’a clickable and the call is not merged
iPhone 13, iOS 16
If you are referring to Cellular Voice Calls then...
SMS, MMS, WiFi calls, Call Forwarding, Call Waiting, Call Merge, Conference Calls, hotspots, and voice mail (Visual or Normal) all are Carrier Specific features. Contact your Carrier (Cellular Service Provider), the agency that issued the SIM / eSIM to you.
If you are referring to FaceTime calls then...
FaceTime group call
During a FaceTime call, tap the screen to show the FaceTime controls (if they aren't visible), tap. at the top of the controls, then tap Add People. Type the name, Apple ID, or phone number of the person you want to add in the entry field at the top. Or tap. to add someone from Contacts.
Make a Group FaceTime call on iPhone - Apple Support (IN)