To change Burger icon from 2 lines to 3 lines, you can follow these steps.
#1. First, you choose the Mobile icon and click EDIT
#2. Next, you click EDIT SITE HEADER
#3. Next, you click on the 2 lines icon
#4. Next, you click on the pen edit icon
#5. Next, you choose the 3 lines icon and click Save on the left of the screen
