iMovie is a part of Apple’s own suite of products for iOS (and macOS), and is a great video editor app for iPhone that you can try. While you may want to use a more powerful editing software on your Mac, iMovie is more than capable of handling video editing on the iPhone. The app is included with the newer generations of iPhones, and you can use it right out of the box to make some awesome videos directly on your iPhone.
Google Duo is essentially Google's answer to FaceTime. It's also one of the most simple video chat apps available. You simply log in, verify your number, and you're good to go. You can video call other Google Duo users like you're making a normal phone call. It also includes a feature called Knock Knock that lets you see what someone is up to before you answer the video call. The app is cross-platform. That means it works between iOS and Android. Rumor is that a web version is coming for computer support eventually. This is about as easy as it gets for video calling apps. It's really very good.
There are more video editing software applications than we can fit into this roundup of the best options, which includes only software rated three stars and higher. The best known among them is probably Vegas Movie Studio, which was recently acquired by Magix from Sony. Sony's product used a very cluttered interface that more resembled high-end professional video editing software from the early days of the craft. Magix has made some progress in simplifying it and bringing it up to par with the competition, but more work is needed for it to be included here.