How do I Create a Collapsible Sub-total?
Step 1: Go to the table where you want to insert sub total
Step 2: From the ribbon select Home | in the Tables group | Sub-Total > Add or select Table Tools | in the Operation group | Sub-Total > Add
Step 3: The Select Rows dialog will appear. Select the rows you wish to include in the sub-total.
Step 4: Select Create collapsible section.
Step 5: Select Apply title and subtotal styles (This will apply the subtotal bold style to the title and subtotal row).
Step 6: Enter "Title description" and "Subtotal description".
Step 7: Click OK to insert Collapsible Sub-total section.