You can send emails to your loved one by signing up to Email a Prisoner:

At some prisons, prisoners can reply directly through the kiosk/in-cell devices. In other prisons, staff print the email, the prisoner writes a reply, and the staff scan and send it via email. You can only use this service if you have your loved one's prisoner number. Email a Prisoner also has an app called eMates. You can find more information on their website.