Once you've added an address to your Address Book, you can quickly access it when creating a task.
In the task creation popup, under either Pickup Info or Delivery Info, click on the field for Address Line 1.
You'll see your Address Book entries listed. Start typing to refine results.
Once you've found the address you want to use, select it to populate the name, contact information, and address details for that pickup or delivery task.
You may see a mix of Address Book results (those with a book icon) and Google search results (with a pin icon).
If you select a Google search result, only address information will be populated, not name or contact details.