If you are editing the Collect Signature workflow in SharePoint Designer 2010, and don't see the following action available:

Send Document to Repository

...it could be b/c that workflow is a globally reusable workflow and not specific to a library or content type...which is what the action "Send Document To Repository" needs.

Try these steps:

  1. Go to the root SharePoint site and create a content type
  2. Go to your target library where you need to do this "Send Document to Repository" action, and associate the content type created in step #1
  3. Go to the root SharePoint site
  4. Open SharePoint Designer
  5. "Copy/Modify" the Collect Signatures SharePoint 2010 Workflow
  6. On "Create Reusable Workflow" pop-up / modal window select the bottom dropdown list "Content Type" you created in step #1
  7. Now when the new workflow is open, type "Send" to filter back 3 options for your workflow "Actions"
  8. You should see "Send Document To Repository" option now available