Do You Know How to Read Vows?

When people read their vows, I guess also for the efficient You're reading off of a paper or something, right? Like I just can't imagine someone being able to memorize something as long as a vow. So how does that kind of work? I will say stay away from using your iPhone. Oh, yeah, that doesn't go well because the the font is small and you're just like looking at your phone really closely.