Sharing a link in iOS: where to place an action button if not in a bar?

I'm going to explain what I've been told to meet: I need to add a kind of "tell a friend" option within a settings menu the app already has (which is a table view). The purpose of such "tell a friend" option is to share a link with other people to invite them to download the app, either via email, sms, or social networks.

I've been reading in iOS Human Interface Guidelines document that it is possible to show a Share extension by tapping an Action button. It looks like this Action button is only suitable for navigation bars and toolbars, and here I have a problem: I think that placing the button in the navigation bar, in my scenario, could be a bit weird since what I've been told to share is a certain short text with a link, I'm not going to share a web page nor a photo which is being displayed in the current view. And I can't place a toolbar since I already have a tab bar at the bottom...

I'd appreciate some ideas to solve this scenario. My app is targeted for iOS 6+ and for both iPhone and iPad.

Thanks so much in advance.