Computers were essential to navigating the Apollo spacecraft to the moon, they were some of the first computers that needed to be small and compact, at least by the standards of the computers of the day. Apollo spacecraft carried 4 onboard computers at launch:
Launch Vehicle Digital Computer on the Saturn V
Apollo Guidance Computer on the Command Module
Apollo Guidance Computer on the Lunar Module
Abort Guidance System on the Lunar Module
The best compilation of documentation on the computers that flew on Apollo is Ron Burkey's research compiled for the Virtual AGC project
https://www.ibiblio.org/apollo/
Information and transcripts from the Apollo Missions with some explanations are available from the Apollo Flight Journal site:
https://history.nasa.gov/afj
For even more technical details on the AGC I recommend CuriousMarc's series on restoring one to working order
https://www.youtube.com/watch?v=2KSahAoOLdU