There's at least two ways to do this. One would be to create a module that only has a button on it in view mode. Then create an edit property that asks for a module id/page id to go to if pressed. You probably want to do tabmoduleid, since you can inspect that object to retrieve the page a specific module is on. Make the edit mode only available to editors/or admins. That way you can use that button to put on any page, and specify the page of a specific module id to go to when clicked at design time, instead of hard-coding it in to the module.

Another way to do it is to have two different view modes of a module. One displays that module and any info/interaction you wanted, and another would only display a button. Then in edit mode also have a property that specifies if the 'display only button' mode is on or off.

As far as specifics on doing this, if you don't understand the above, it's fairly basic DNN stuff. I would go check out some videos on youtube on introduction to module development. Hope this helps!