Describe what you did. That should make it easier for you and anyone looking at the project to understand what's been going on.
E.g. If you're fixing the docs, make sure to mention the section or the exact doc you edited. Here's my latest PR. I made it easier for the maintainer to understand what I've done, without him having to look at the diff. This is a rather dumb example, but imagine a larger doc with more changes.
Also, I tend to name the branches in a meaningful way, so that when you track CI builds, you know what's been going on.
E.g. My branch will have mm since those are my initials and short-description-of-what-is-being-updated
mm/fixing-documentation
Little things like that keep your team headache-free.
P.S. I just realized I didn't do exactly that in my example, sorry Sandeep 😂 However, when it's a major PR, I do follow all the rules.