Most eLearnCommerce Installations do not require Cron Jobs, this tab will only show when they're actually required.
Note : Cron Jobs may appear to be working, even if they're not, it may take 5 minutes to 1 day ( depending on what Cron Jobs need to be executed, which depends on the features you have activated )
eLearnCommerce Cron Jobs are working
eLearn Commerce Cron Jobs are not working
eLearnCommerce Cron Jobs, how to fix
Contact your hosting provider, and ask them why the Cron Jobs are not being executed, normally it should work out of the box.