You will know that it’s time for you to link your accounts when Securus sends an email communication to the personal email address used as your JPay username advising you what to do and providing a URL explaining the steps to link your JPay account to a Securus account. Once your account is linked your stamps and message history will be transferred to your Securus account.
If you did not receive the email go to https://securustech.online/#/jpay and enter your JPay username and password.