Please follow the the steps as below -
Open the Dialler App, go to “Settings” –> “Calling Accounts” –> and enable “Vibrating for outgoung calls accepted”.
Then open the Settings, goto “Sound & Vibration” –> “Vibration” –> and enable “Touch Feedback”
After this, there will a small vibration when the party who’s called, answers your call.
Note : the vibration doesn’t work when Battery Saver’s On