does i phone 12 dual sim also has esim ?

No.

If it has an eSIM, it will also have a single SIM slot.

If it has dual SIM slots, it will not have an eSIM.

Update - See stedman1’s response. It is better than mine was.

Using Dual SIM with an eSIM - Apple Support

The model with 2 SIM cards has 2 physical cards only. The other 2 sim phones have 1 physical sim and 1 esim.