If you are looking to append or prepend to a document in eFileCabinet (without having to check the document out of EFC and modifying the pages in a pdf editor), make sure that you have a local copy of the file you wish to append/prepend, rename it to match the name of the file in eFileCabinet exactly (if the names don't already match), then perform the following steps:
1. In eFileCabinet, navigate to the drawer/folder containing the file, right click on it and select "Upload."
2. Navigate to the file in your local directory, select it, then select Open/OK.
3. A duplicate file options window will appear. Choose Append or Prepend in the drop down, then select Continue.
This will create a new version of that file with the appended/prepended page(s).