If you currently are frustrated with your video quality when sending from Android to iPhone or just in general, there are some options that can help without compromising quality.
Third Party App
You can send the video via Facebook Messenger, Send Anywhere, WhatsApp, Viber, etc. If you send a video using any of these apps, it should reach your recipient with its quality intact. You will just need to have the other person use the same app you use.
After you take a video, save it to Dropbox, Google Drive or another cloud-based storage choice. You will then be able to send a link with the full-sized file.
Simply log in to your email, create a new message, choose the video you want, and press send. It will arrive in the same quality as it was sent. The email size limit varies but is usually 20-25 MB, but short videos should go through without any hiccups.