Use Secured Signing App with Google Drive

Right click your document in Google Drive, choose "Open with", then choose "Secured Signing - Secure Digital Signature"

The Google Drive takes you to an authorization page to allow the privileges that needed in Secured Signing App. Choose your Google Account, the click Allow button to finish the authorization

1. Choose Google Account.
2. Click Allow to authorize.

Once authorized, you need to login to Secured Signing with your account. Register one if you don't have. Then on the "Authorization" window, authorize your account.

Now your google account is connected to Secured Signing account, you can process your signing.