Any Magix video editing app, like Movie Edit Pro or Video Pro X, allows the user to select a single frame from a video and export that frame as a still image, which can be edited and/or manipulated in any way and using any image editing app that the user wishes to use.
The actual process of selecting the frame and creating the exported image is quite straightforward. if you need help with the process, post back, making sure to tell us exactly which video app you are using.