and how an i know which wallet create segwit address and if these addresses are cheaper why all people use other addresses ?
Some people use legacy addresses, just because they don't know the difference and advantages of segwit addresses,
Also, some services don't support segwit addresses, because they are outdated.
why these addresses are cheaper ?
Before segwit soft fork, transactions were being prioritized based on the paid per byte. But now transactions are prioritized based on the fee paid per vbyte (a unit for measuring virtual size of a transaction)
Segwit transactions have a different format which makes them have a lower virtual size. This causes segwit transactions to be cheaper.