It’ll just wipe all your data, user apps, and restore all settings to default for your current ROM. It’ll just wipe all your data, user apps, and restore all settings to default for your current ROM.

Can we factory reset a custom ROM?

Basically exactly as a new phone, just with a custom ROM. Just use wipe data/factory reset function in TWRP and use the advanced wipe options.

Does factory reset remove root?

AW: Does factory resetting remove root? No. You have to flash the stock image.

Can you uninstall custom ROM?

Just Download the stock from any website and then place (or Download the stock/AOSP ROM for your device) in the SF card. After go to the phone recovery option on your phone and then select “Wipe Everything” or “Clean to install a new ROM” whichever is available and then clear data and cache.