Adding Local Share Button to Posts

I am utilizing the Ultimate Member theme which allows for social media activity and etc. The issue I am having, is when a user creates a post you only have the option to “like” the post or “Comment” on the post. I would like to add an option where users can “share” a specific post and add it to their activity feeds for their followers/friends to see.

I am trying to look for a plugin that will assist me with this. Unfortunately most plugins relating to this issue simply add sharing buttons that direct the post to a completely different social media site.

Any ideas on how I can add this “share” button to user posts that will in turn repost the selected post to their own activity feed for reference?

The page I need help with: [log in to see the link]