Spammers find your email address using software called E-Mail harvester, E-Mail harvesters are bots that visit websites, extract the email addresses written explicitly in websites pages and store them in databases to send them spam later, additionally, this harvested address will be sold and shared between spammers and in result, you will get more spam.
So, step 1 is to remove any email address explicitly written on your website like in the about or contact pages, instead, use secure form-to-mail contact form.
SpamExperts is advanced spam filter that will stop %99.99 of spam within few minutes, 2MHost offer this filter as hosting free addon with some packages and paid addon for some other hosting packages, for more information, please check SpamExperts page or contact us.
SpamAssassin is a spam filter available for all hosting accounts, you can access it from cPanel > Spam Filters
When enabled, Spam Filters will mark suspicious email messages as spam. The filter will add a “***SPAM***” tag to the subject of the messages whose calculated spam score exceeds the Spam Threshold Score.
After that, you can configure the filter to move the spam to a separate folder (Spam Box) or to auto delete it.
You can adjust Spam Threshold Score to fit your needs form, The lower score is, the more restrictive filter will be.
If you are using SpamExperts then there is no need to enable SpamAssassin.