The crontab is a list of commands that you want to run on a regular schedule, and also the name of the command is used to manage that list. The crontab stands for “cron table,” because it uses the job scheduler cron to execute tasks; cron itself is named after “chronos,” the Greek word for time.
In crontab man page, Each user can have their own crontab. These are files in /var/spool/cron/crontabs , files are not intended to be edited directly.
Command to edit cronjob as username:
crontab -e username