Hi Harveyj,
As mentioned by "TestScreenName" above, Export PDF is not an App. Its an online service that you can access via Adobe Document Cloud using any web browser.
Also, you can download the free desktop application Adobe Acrobat Reader DC and start using the service.
Follow the steps mentioned below, to activate the subscription.
1- Export PDF is an online service that you can use online via: Adobe Document Cloud
2- You can also use the services through free desktop version of Adobe Acrobat Reader DC: Adobe Acrobat Reader DC Install for all versions
3- “Sign In” using the email (Adobe ID) under which you have subscription registered.
4- For detailed description of how to use the Export PDF service, you may refer to- Using Adobe Export PDF
You may refer to the following link for any troubleshooting: Troubleshooting Create PDF, Export PDF, Adobe Send, Fill & Sign … services(PDFPack or Document Cloud Services).
Let us know if it still doesn't work.
Regards,
Akanchha