Yes, most people use Face ID on their iPhones, but many still retain a passcode. If you wanted to go totally secure on your iPhone, you could turn off Face ID and just use a passcode. There may come a time when you wish to change the passcode on your iPhone. Here is how you do that.
To change the passcode on your iPhone you need to go into “Settings”, scroll down and tap on “Face ID & Passcode”.
You will be required to enter your current passcode to continue.
In the next window, scroll down to “Change Passcode”.
You will have to enter your old passcode again here.
In the next window, you can enter a new passcode. But, pay attention to the “Passcode Options” button.
If you tap on “Passcode Options”, you are presented with choices for the type of passcode you can create.
These days, security experts recommend a passcode of at least 7 digits. The old 4 and 6 digit passcodes are too easy to break.
It might not be a bad idea to change your iPhone passcode occasionally. Especially if you have given it out to other people.