What is it?
Spam isn't a good thing. You are getting a fake email, probably with a virus attached. A smart idea is to get one use email accounts.
How to avoid
When you receive spam, you are getting a fake email from somebody who sent it out to thousands of people. Don't reply! You are just confirming that your email is real. It is a good idea to avoid the spam email, delete it, or move it to a spam folder. Never download links from an unknown email. If you know the email, be sure you know what they have sent you.