first launch the filmorago app. Import the video which you want to crop. Play the clip to check it.
click on the video on timeline to open other editing options.
Click on crop option. In preview window drag the crop box to the place which you want to cropped video.
Or click on preset crop option at bottom.
click on reset option to get back original video.
Once you finalize the location to crop video click on tick sign.
Play the video to check it