Yes you can.
If you choose to enroll in Face ID, you can control how it's used or disable it at any time. For example, if you don’t want to use Face ID to unlock your device, open Settings > Face ID & Passcode > Use Face ID, and disable iPhone Unlock or iPad Unlock. To disable Face ID, open Settings > Face ID & Passcode, and tap Reset Face ID. Doing so will delete Face ID data, including mathematical representations of your face, from your device. If you choose to erase or reset your device using Find My iPhone or erasing all content and settings, all Face ID data will be deleted.
Sure. You don't have to Face ID and a login code is required after you power on or haven't used Face ID in a while. Face ID is optional.
Thank you all. Appreciated.Yes you can.