SMS isn’t a file sharing service. It’s an older protocol that was never designed for media. Back when it was developed no one could foresee phones doing what they are doing now. The screens had a very specific amount of text characters it could display. It might be as limited as 10 characters in two rows. <—- Just that last sentence alone would’ve been four rows you would have to scroll through two rows at a time.
But luckily as technology has advanced we have options. Instead of demanding all phone carriers to update an antiquated SMS protocol people can just make an app letting them talk to anyone around the world and send most any file. It’s best you try to communicate with that person through email or another app like WhatsApp. Your iPhone also has the ability to store larger files such as family vacation movies in your iCloud storage, allowing the recipient to download it through email. This is something other phone operating systems still don’t have built-in.