Is there handover to/from Wi-Fi calls?

Yes, handover to/from Wi-Fi calls is possible both ways - it just requires that VoLTE (minimum 4G) is available.

A call from the mobile network must be on VoLTE (4G) to perform handover to Wi-Fi calls (a Wi-Fi where the SIM is approved/recognised).

Similarly, handover from a Wi-Fi call requires VoLTE (4G) to be available outside of Wi-Fi coverage.