Change Users & Groups Guest user preferences on Mac
If you’re an administrator of your Mac, you can let other people use it temporarily as guest users without adding them as individual users.
To change these preferences, choose Apple menu 
> System Preferences, click Users & Groups, then select Guest User on the left. If a guest is logged in to your Mac now, you can’t select Guest User.
Open Users & Groups preferences for me
Option | Description | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Allow guests to log in to this computer | Lets others log in to your Mac without entering a password. Guest users can’t log in remotely. If you select this option, you can also select the following one. If FileVault is turned on, guest users can access Safari, but can’t access your encrypted disk or create files. Select the Limit Adult Websites checkbox to prevent guest users from accessing adult websites. | ||||||||||
Allow guest users to connect to shared folders | Lets a guest user access shared folders from another computer on your network. | ||||||||||
Add | To add a new user or group, click the Add button | ||||||||||
Lock | Locks or unlocks Users & Groups preferences. Click the lock icon | ||||||||||
and Remove 
Guest access works with the Find My app to help you find your Mac if you lose it. You can locate your Mac if someone finds it, logs in as a guest, and then uses Safari to access the internet. See Set up the Find My app to locate a missing Mac.