Access 2000 Fill-In Form

I assume you mean when adding new records:
Set the default value for each field where you want a default value in the database table. You can do this when you open a table in design view, click on the field you want to set a default for, and at thebottom in the Field Properties window set a value for the default value property.
If you are not adding new records, but editing, and the field already has a value, a command button can be add next to the field and when the user clicks it, it then retrieves the default value from the field property and replaces the current value with the default value. And in addition to that, you can add a main command button or menu point which replaces all current field values on a form with their default values.
The other properties can also be retrieved, such as the Caption or Description properties. These could be used for labels captions or even for help tips that the users can see when they click on a certain field.