As per the description above, you are not able to edit a PDF with the service of Adobe ExportPDF, Is that correct?
With the Adobe ExportPDF service, you can easily turn PDF files into editable Word, Excel, PowerPoint, and RTF (Rich Text Format) documents. But you cannot edit PDF files with Adobe Export PDF. You need Acrobat DC to edit PDF files. See Adobe Acrobat Pro DC: PDF converter, convert PDFs from anywhere.
You can use the service of Adobe ExportPDF through the URL https://cloud.acrobat.com/exportpdf with your Adobe ID and password on a browser like Chrome, or Firefox, or Safari.
For troubleshooting, you may refer to Troubleshooting Create PDF, Export PDF, Adobe Send, Fill & Sign … services(PDFPack or Document Cloud...
Feel free to update this discussion in case you need further assistance.