How to set up a cron job

Cron is a time-based job scheduler. Several Magento features require the correct setup of cron in order to schedule activities to occur in the future. In order to set up a cron job on UNIX/BSD/Linux you should type command crontab -e. If you are logged in as root user you may edit a specific user’s crontab using command crontab -u user -e.

The command will open an editor where you should add a cron task:

*/5 * * * * /bin/sh /absolute/path/to/magento/cron.sh
*/5 * * * * /absolute/path/to/bin/php -f /absolute/path/to/magento/cron.php
*/5 * * * * curl -s -o /dev/null http://www.yoursite.com/absolute/path/to/magento/cron.php > /dev/null
*/5 * * * * wget -O /dev/null -q http://www.yoursite.com/absolute/path/to/magento/cron.php > /dev/null

where /absolute/path/to/magento is an actual path to your Magento root folder.

To configure Cron in Magento 2 you can check this guide.