HTC One User Manual page 217

3. To help protect your data, set a password for your backup. Be sure
to remember this password. You'll need to enter it again when
restoring messages.
If you don't need a password, select Do not password protect this
backup.
4. Enter your email address.
5. Compose your email message, and then send it.
Restoring text messages
1. Open the Messages app.
2. Tap > Back up/Restore SMS > Restore.
3. Choose how you want to restore the messages, and tap Next.
4. Tap the backup to import.
5. Enter the password you've set for this backup. If you didn't set a
password, select This backup file is not password protected.
6. Tap OK.
To restore text messages that were backed up via email, open the email
message with the backup file attachment from the Mail app. Tap the
attachment to download it first, and then tap it again to open the backup
file to import. Enter the password you've set for this backup or select This
backup file is not password protected.
Sync, backup, and reset 217