Yes, it is very much possible to have a mobile app for any Shopify plan i.e Advance, Lite, or any other Shopify plan. If you already have your website running, getting a mobile app for it doesn't need to be complicated. There are many apps available at the Shopify store which can help you to convert your store into a native mobile app.
I suggest you go with the MageNative app one of the most trustworthy and reliable app development companies, having more 200+ reviews on the Shopify store.
MageNative provides you the app with no work to be done at your end except to provide your requirements and install the app. And your mob app will be ready in 1 business day. Along With many add on integrated features for your app and all this available at very low rates., You will also get 24/7 full support and response over mail live chats Skype and over Whatsapp also we are now providing 30 days free trial period on our app.