Lets say
0 0,12 * * * command
is what you write a cron job, which runs twice a day on 00hour and 12th hour.
How to write to do cron job twice a day but lets say on 2pm and 2am?
cron runs on a 24 hour clock starting from 0 as midnight and 23 as 11 pm. As such you'd simply have to replace 0,12
with 2,14
Try this Cron Job Script Calculator: http://www.csgnetwork.com/crongen.html
Or try Crontab Generator: https://crontab-generator.org/