I don't remember much but the cover was pretty simple, just one color. Gave me Stargirl vibes. It was about a group of kids. They had an acronym for what they called either themselves or the adults and it had the word people in it? It was a series of 3 or more books. One of them (or all of them?) have a spaceship involved. It was a super simple book, nothing like Series of Unfortunate Events or Hunger Games.
Possibly this is the AstroKids series by Robert Elmer. It's about some kids--Buzz, Miko, Mir, DeeBee, and Tag--who live on a space station. The kids call themselves the AstroKids, which doesn't contain the word people but it does contain the word kids.
They are simple books, maybe a second or third grade reading level. The covers are simple with one primary color, as you said. There are more than three--the boxed set I have includes five, but I believe there are ten altogether.
The first book is The Great Galaxy Goof.
Here a link to the whole series on Goodreads.