It's hard to stop spam email entirely, but you can filter it, discard it, deliver it to the selected folder, etc.
How to Create an Account Level/Global Email Filter?
1- Log into your cPanel account.
2- In the Email section, click on the Global Email Filters Icon.
3- Click on the Create a New Filter button.
4- Enter a name for the filter in the Filter Name text box.
5- In the filter rules, you can filter email with many options, and should you want to deal with email, which contains a word like Lottery or other words, then in the first list box select Body and select Contains in the second list box.
6- Under Actions list select Discard Message.
7- Now Click on the Create Button.