Readers of webcomics aren't generally going to expect an AO3 style experience -- you know, fanfiction where all the tags kinda set up the kind of story this will be, the sorts of tropes you can expect, and which characters are going to be in it. You don't need to do that.
In webcomics, generally, the description of a comic is kept short to give folks an idea of what's interesting about the story. In order to find out if it's your kind of story or not, the comic is right there, you can just read some of it and see if it's interesting. Even for a comic that has a lot of words, I don't think a super long summary is wise -- a long, long summary betrays that the creator might be worried the comic doesn't speak for itself.
So, looks like this is your comic?
This is a story about a girl who is living her life disguised as a boy. Since the age of 12, when her family was killed by a serial killer, she has taken on the identity of her brother, living together with her uncle and cousin as a custom arranged witness protection program. Seven years on she is suddenly recognized for the first time by an old childhood friend. At the same time she manages to get into a heap of trouble with the law. As her cover is slowly unraveled and she might be put in serious danger, she is also falling hard for a police investigator who shows a strange interest in her.
What happens when you are living a life based on lies. Living and making ends meet outside the law. Living as another person. What if even the love is based on lies.
Slowburn romance with all the trashy tropes. This is a novel disguised as a Webtoon.
"girl living as a boy" is the basics, and you could throw in a major thing that happens as the hook of the story -- without having read it, "suddenly she's recognised" sounds like a point where things might suddenly change, for example. And I like "slowburn romance with all the trashy tropes" actually! Advertises it to folks who go "heck yes sign me up for trashy romance tropes."
So something like "This is a story about a girl living her life as a boy to protect her identity, when one day she is suddenly recognised by an old childhood friend," maybe something about life being based on a lie when that lie unravels, and the line about slowburn romance, and you're good. Or, if the police officer romance is a bigger part of the story, you could focus on that -- "[main character] is living her life as a boy to hide her identity, but she's falling hard for a police investigator who's trying to figure her out. How does love work when your life is based on a lie?" etc etc
There's a lot of different ways to do it, but if you try to squeeze every interesting thing into that description, it's gonna be less an intriguing story hook and more like a list of things that happen, which is the probably the least interesting way to encounter a story.
When I'm looking at a book or movie and deciding whether or not to read it, my friend isn't gonna just list out the things that happen at the start of the story and why they happen -- they're going to say "oh my gosh, no, you would love it, it's about a princess who runs away to join the dragons to avoid marrying a prince, and later there are evil wizards!" That's all your summary needs to be.
