Microsoft added a new personalization feature: “A field can be configured as required by users via personalization or by developers (with the Mandatory property). While unbound controls, that are required, show a red visual indicator, there is currently no enforcement that these fields must be filled in before saving or leaving the form. This preview feature adds that enforcement, so that required unbound controls perform as expected.” The feature is in preview in version 10.0.19.
In standard D365FO it has not been possible for users to setup additional fields that are mandatory when a new record is created. The mandatory field(s) have a red visual indicator.
When you personalize a field a new check box “Required” is available.
When you select that a field is required, the field now has the same indicator as standard mandatory fields.
If you try to save the record you are now allowed to do so, and you are told that the reason is that: Field ‘Main account category’ must be filled in.
This feature (still in preview) fulfills a requirement from many customers. When used it will increase the quality of master data.