After you've displayed the query you want to modify in Design view, click above the field you want to delete.
The column is selected. Press the Delete key on your keyboard.
The field is removed. Click the Save button on the Standard toolbar in the main Access window to save the query design. When you run the revised query, this field will not be included.
If you included fields in your query that are not pertinent to the query results, you can delete the fields. For example, if you used a wizard to build your query, you might have started with all the fields in the table and then realized that you only needed a select few. If so, you can remove any fields you don't need.
If you prefer, you can simply hide a field. For example, suppose that you need to use a field in your criteria, but you don't necessarily have to display that field in your results. To hide it, uncheck the check box under the field's name in the Show row.