When I was using the previous version of Adobe Reader with Adobe PDF Pack, Annual Subscription I was able to import my signature from either another PDF document or a Word document into a PDF document that I want to sign.

I would need a bit more information on what your signature workflow was before, I'm not aware of a workflow in Reader XI using a Word document, only in Acrobat using a Digital Signature and applying the Word document as the appearance.

As far as I know there are basically two signing workflow/options. 

1) If there is an actual "signature field" in the PDF you can use a Digital Signature, and an option once a digital signature has been placed is to "Create an appearance", for the appearance you can use an image or PDF file (in Acrobat Pro you could use a number of additional file types incuding a Word Doc).  That has not changed from Reader XI to Reader DC...

2) If there are no actual form fields (not fillable text boxes, when clicked the text field does not get the cursor focus), or you need to sign and there is not an actual signature field (similar, nothing happens when you click it) you can use the "Sign" panel in Reader XI, or the "Fill & Sign" tools in Reader DC...

This is where there has been a change, the new "Fill & Sign" tools (which are entirely new for Reader DC, the same tools as https://cloud.acrobat.com/fillsign) do not have the "PDF" option for importing a signature, only "Image" file types.  If this is what you were using before you can extract the image of your signature from the PDF or Word file you were using and then use that image in Fill & Sign.

Thanks,

Josh