YA Romance about a world were when you receive a specific red letter, you will die soon

[Cameron]

YA Romance about a world were when you receive a specific red letter, you will die soon and must get your affairs in order. The Main character spends the entire book trying to escape death and (by accident) is stuck with her personal grim reaper being right next to her the entire time. The cover had a red letter being pushed through a mail slot, one of the ones at apartment complex's, not through a door. the cover also had a red border and the mail box thing was kind of yellow/beige. The main character wants to find love for both her and her best friend before she passes this border thing into the dead world, and the grim reaper dude is like "I can do that, but its a cavalier request" but that ends up being a clue, At some point she finds out that said best friend is gay and her own love interest is ALSO dying soon. i read it between 2016 and early 2020. The grim reaper people moved like they were moving through water and sometimes you would see them walking to like a coffee shop. The MC's best friend is obsessed with these people and was kind of a conspiracy theorist.

[Rosa]

The Wrap-Up List

[Kris]

Rosa's suggestion of The Wrap-Up List by Steven Arntson sounds like your book. Here's the Google Books preview:

https://books.google.com/books?id=pgK... There are different cover images.

Quote from the book:
"You expect me to do everything?"
"Well ... yes? ...

"Request anything?" I say.
"A cavalier request."