Time Tracker has various entities for its objects such as projects, users, tasks, time records, etc. When creating a custom field, you may associate it with an entity type. Entity type selector for custom field
Associating with time adds custom field to time log entries. For example: customer support ticket number.
Associating with user adds it to users. For example: cost center or resource type.
Associating with project adds it to projects. For example: project number or account.
Depending on how you associate custom fields, things look and work differently in various views and reports.
