How do i get a sharing link for the app if I'm using UIActivityViewController?

I'm developing an iOS app and i haven't bought the dev licence yet, my app is about facts and jokes based on a more categorised view. So i added a button to share the same using UIActivityViewController and the string I'm passing is the joke and an appended string which says "Check out this app (in this place i want to include the app store's link so that others could connect to it)"

Any help would be appreciated. Thanks.