To insert the field within the table, click in the row below where you want to add the field, and then click Insert Rows on the toolbar.
To add the field to the end of the table, click in the first blank row.
In the Field Name column, type the name for the field, following Microsoft Access object-naming rules.
In the Data Type column, click the arrow and select Yes/No.
To display True/False or On/Off instead of Yes/No (the default) in the field, in the bottom part of the window on the General tab, click in the Format box and select the format you want.