how to send a email with planned task

Pipe the output to mailx or enable notifications for the system. cron will email output by default.

Create a scheduled job and add this as command

mail -s "Sending mail works" yourname@yourprovider.xx < /dev/null

If you want to add a message to the mail, you can use

echo "sample message" | mail -s "sample mail subject" yourname@yourprovider.xx