Id, userId, and Encharge Anonymous ID
There are a lot of IDs in Encharge, so this might seem overwhelming at first. Fear not! We'll explain each one below.
Every person in Encharge has an Id. It's impossible for a person to exist in your account without an Id. Both anonymous and identified people have it, and it's essentially used to identify people in Encharge, even when they are anonymous.
The userId is used to match users from your product (web or mobile app) to people in Encharge with the API. When you bring users from your product to Encharge through the API you would map the user IDs in your app with that field.
When a person receives an userId they become identified, even when they don't have an email address. People with recorded userId count towards the subscribers on your billing plan.
Encharge Anonymous ID
Encharge Anonymous IDis a field used when a person is tracked through the JS Site Tracking in Encharge. It's a technical field required for Encharge to track people with the tracking, and you shouldn't be concerned with it too much.
A person with the Encharge Anonymous ID is still considered anonymous.
When connected, other apps like Segment and Salesforce could create additional IDs for people in your account. For instance, people brought from Segment will have the "Segment Anonymous ID".
Generally, you shouldn't be concerned with these IDs. A person with any of these IDs is still considered anonymous unless they have an email or an userId.