Songfacts®:

• Linda Perry wrote "The Letter" for the Hulu documentary Kid 90, which centers on Soleil Moon Frye, who as a child starred in the '80s sitcom Punky Brewster. Moon Frye directed the film, which uses footage she shot in the '90s of her exploits with other child stars like Leonardo DiCaprio and Corey Feldman.
  
  The song was inspired by a scene in the film where the adult Moon Frye reads a letter she wrote to herself when she was 16.
• In a Songfacts interview with Perry, she talked about how writing a letter compares to writing a song. "Writing a letter takes thought, and it has to be deliberate," she said. "There's an agenda. There's an intention. When you sit down and pick up a piece of paper, you're going to write a letter, right? You're going to sit there. 'I'm going to write a letter, and this is what it's going to be about.' You go in with an intention.
  
  When I write music, there is no intention, there is no agenda, there's nothing. I don't have a line, I don't have a subject matter, I don't have anything. I'm just sitting at the piano or picking up a guitar and I sit there and it's all happening right then at the exact same moment."
• Perry shot a video for this song with director Don Hardy; they worked together on the 2020 documentary Citizen Penn. Perry hadn't made a video since the '90s, when she was lead singer of the group 4 Non Blondes, so she was nervous. Hardy used tight shots of Perry (with her signature top hat) and projections to go with the theme of the documentary. Footage from the film is interspersed throughout.
• "The Letter" was the first Linda Perry solo release since her 1999 album After Hours. In the 2000s, she focused on writing for other artists, and wrote hits for Christina Aguilera ("Beautiful"), Pink ("Get The Party Started") and Gwen Stefani ("What You Waiting For?"). She started working on music for films in 2018, collaborating with Dolly Parton on the soundtrack for the Netflix movie Dumplin'.