If you’ve got a fitness app, you might have segmented your potential audience into 2 groups. Men who want to get huge lifting weights, and men who want to get ready for a marathon. As you can imagine, they have completely different goals, and their interests and behaviour will reflect that. You need to take this into consideration when you create your images.
Free video editing software often comes with legal and technical limitations, however. Some widely used codecs require licensing fees on the part of the software maker, meaning they can't offer free software that can handle these standard file formats. That said, the impressive open-source Shotcut does a lot of the same things that the paid applications in this roundup do, including things like chroma-keying and picture-in-picture. Shotcut is completely open-source and free, while another free option, Lightworks has paid options that remove a 720p output resolution limit. Note also that both Shotcut and Lightworks run on Linux as well as Windows and Mac.