There is a different menu on Desktop & Mobile.
If you want to show the Mobile menu, let do as these steps:
+ Basel – Multipurpose Ecomerce Shopify Theme
Go to Sections -> Mobile side menu
Choose the menu show on mobile
+ Gecko – Responsive Shopify Theme & Elessi – Responsive Shopify Theme
Go to Theme settings -> Header -> Mobile menu -> Choose the menu
Thank for reading!