We provide most of the time only the latest version. But if you cannot find the version that you want, you must create a "media request" service request in MOS. The instructions are available in MOS doc ID 1071023.1. This is also applicable if you just want a URL for the download.
Can you try again?
Make sure you went to 'Patches and Updates' tab, click on the "Product or Family Advanced" tab, type in 'Oracle Documaker' for the product and select 'Oracle Documaker 12.1' for the version -- then search.