If you are on android you can back up to gmail with this app. http://www.howtogeek.com/112852/how-to-backup-your-text-messages-to-your-gmail-account/
Otherwise you can back them up to an SD card directly from your message app.
If you are on android you can back up to gmail with this app. http://www.howtogeek.com/112852/how-to-backup-your-text-messages-to-your-gmail-account/
Otherwise you can back them up to an SD card directly from your message app.