Assuming it’s an Android phone, tap on Settings >> Network & internet >> Mobile Network >> Preferred Network type . You should see all the Mobile Network technologies supported such as 2G, 3G, 4G and 5G. If 5G is listed, then your phone supports it.
Read moreWhat is APN called in 5G?
In 5G, Data Networks are specifically identified using a DNN. The DNN is typically in the form of an APN (Access Point Name ).
Read moreHow do I set my phone to 5G?
Switch between 2G/3G/4G/5G – Samsung Android
Read moreHow do I change my 5G settings on Android?
Switch 2G / 4G / 5G
Read more