Hi @synergetic
From what I understand, you want to show dropdown menus for state and city fields during checkout. I think AppMySite supports the WooCommerce Checkout Field editor, so if you setup your website checkout with this plugin (and include dropdowns for states and cities), the same should sync to the app as well.
I found this on their support section: https://www.appmysite.com/support/kb-doc/woocommerce-checkout-field-editor/
Hope this helps.