Turning off passcode
How do I turn off my iPhone passcode
iPhone XS
Go into Settings>face ID and passcode.
Tap Turn Passcode Off.
Not that this will also disable face id. Face ID requires that you have a passcode set on your phone.
If you have a corporate email account on your phone, it may be impossible to remove the passcode unless you first remove the corporate email account. Corporate Exchange administrators can enforce policies on connected devices, including passcode requirements.