Email

How can I make it safer?

Consider adding a program like "Spam Arrest" or "TMDA" to your child's email. These programs only allow people on the "allow list" to send an email to your child and force unknown email addresses to confirm themselves before sending email to your Inbox.
With your child, help set up their email account. Know your child's login information and email addresses. Teach your child to create passwords that others can't easily guess, and that contain a combination of numbers and letters (both upper- and lower-case).

Set the expectation that you will monitor your child's online activities, as the Internet is a public place. Supervise your child’s online communications and discuss the qualities of healthy and unhealthy friendships. The important thing to remember when supervising online communication is that it’s not about interfering with a child’s ability to practice the art of making friends but rather about lending an adult lens to the situation in order to know when a child may need some assistance with a situation.
Tell your child not to open any emails and/or email attachments if s/he doesn't know the sender.
If your child comes across something or someone that makes her/him feel uncomfortable, explain that s/he can tell you without fear of losing computer privileges.