To update the loan information, click on the client you wish to edit from your "Client" list, then click "preview digest" to open/edit their digest. Once the digest loads, you'll see a screen like this:
You'll notice on the left side, there is a faded-out window pane titled "Your Current Mortgages"--click on it to pull the pane forward. You should now see a screen like this with the loan info pulled forward:
Now, click "Edit" to update the loan information. Save the changes and the digest will update accordingly (see screen shots below). Note: If no loan exists, you will be prompted to add a loan. You can also add a loan by clicking the "+ Add" button located to the right of "Your Current Mortgages." You can also view past mortgages by clicking "View you past mortgages."
You can update the loan for any of your clients by following this process.