You can find instructions on running a crontab in Linux as the www-data user in a tutorial by TecAdmin.
Running a Crontab as www-data User in Linux
In a Linux system, the cron daemon is used to execute scheduled commands or scripts. By default, cron jobs run as the root user. However, sometimes it is necessary to run cron jobs as a non-root user, such as the www-data user. The www-data user is often used by web servers to run web applications
