For some objects, system fields such as “create date/created at”, “created by”, and “update date” are filled in automatically upon record creation for most CRMs.
For the “create date” and “update date” system fields, the CRM usually enters the date/time of the migration (the moment a record is created via API). For the “created by” field, the CRM will typically automatically set the field to the user under which the migration was performed under - since technically, this user is the record creator via API.
In order to preserve these field values and ensure accurate CRM history, we suggest you create the necessary custom fields in your target CRM. Once created, you can reload the wizard page, navigate back to the mapping objects step and re-match those fields as shown below.