At Planning / Setup / Location Preferences, select the Sales Order Prefs tab. Check the Allow users to create DT from Sales Order in Agvance Sales app option, then choose Save.

Mobile Sales App Setup
In the Mobile Sales app, at Menu / Sales Orders, turn on the Create Unloaded Delivery Ticket option.

When creating the Delivery Ticket, the Type must be set to either Pickup or Deliver and the Status set to Approved.
Creating a Delivery Ticket from a Sales Order displays the following message:
Delivery Ticket Created
A Delivery Ticket was created with id XXXX
Tap OK.

The Sales Order is marked processed.