User keycodes are tied to an individual account and have the advantage of controlling each user's permissions to arm and/or disarm the alarm system through their unique keycode and site permissions.
To generate a keycode you will need to be an Org Admin. Once you have confirmed your accounts permissions, you can go to All Products > Admin > Org Settings > Users > Select Account > Generate
The user must have the Alarms user permission in order to use this code tied to their account. However, if the user is a Site Admin, they will be an Alarm user by default for that site. This allows you to give users permission to arm and disarm a site and limit camera viewing.
Furthermore, if there are many alarm sites that a user needs to arm and disarm, you can designate those permissions instead of configuring Alarm keycodes for each site for the user.
Alarms Keycodes are not tied to an individual account instead they are given a generic name. These serve the purpose of creating a one-time keycode for a group of people to use such as janitorial staff or a master keycode in case of emergencies for that specific alarm site.