You can adjust the amount of drop used while taking off items in Digital takeoff via the AddedDrop field on the Takeoff mode speedbar.
After setting up your drop amount, you can apply the drop to your annotations. After you finish drawing an annotation, right-click on the main window and choose either Add Vertical Drop and Finish or Add Horz. Run and Finish. This will finish the annotation takeoff and add the set drop to the calculations.
Note: For Electrical Takeoff you must use the Takeoff Drop button on the Digital Takeoff Link Bar to successfully add drop.
Digital Takeoff will represents added drop with a black, dotted line as the below image illustrates:
You can then switch to Standard Takeoff to assign an item to the annotations as usual.
Note: Installation Types can also be assigned to drops, as they are defined as separate items in Standard Takeoff.