Video Completion (preferably USA-based freelancers)

I have 2 videos mp4/mv4v format they both need a "call to action" button/link embedded in the last 7 to 10 secs of each video so that the viewer can click it and be directed to my shopping page. I would like this so that anyone who downloads the video or shares it, they will not have to provide the shopping information. The videos are on my new Youtube channel but I do not have enough viewers to do this through the Youtube video creator/manager. Also, I want the feature to be embeded so that it will work on multiple platforms when sharing the videos through other social media platforms like Facebook, Instagram, Twitter, etc.