One of the best and most full featured mobile video editing applications is KineMaster. And despite how much it can do, this little app is nice and easy to use. First you must pick all of the images and clips you want to include in your final creation. After putting these in order you can adjusts volumes, colors, clip speed, effects, transitions, shorten sections, crop the image... You can even draw and voice over the video if you want. Then, when you have everything in place, you can share it but yes, if you want to lose that watermark you will have to pay.