When you enter data on pages in Dynamics 365, certain fields are marked with a red asterisk. The red asterisk means that the field must be filled to complete a certain process that uses the field, such as posting a transaction that uses the value in the field.
Even though the field contains a red asterisk, you are not forced to fill in the field before you continue to other fields or close the page. The red asterisk only serves as a reminder that you will be blocked from completing a certain process.
In the Customer Card window, the red asterisk appears in the Name field, in the Tax Area Code field, and in the posting group fields to indicate that you cannot post a sales transaction for the customer unless the fields are filled.
In the Item Card window, the red asterisk appears in the Description field to indicate that you cannot enter the item on a document line, such as a sales order, unless this field is filled.