Are you trying trying to convert several documents into a single PDF? If so, you can use the Combine PDF functionality in Adobe PDF Pack. Here are the instructions:
Sign in to your PDF Pack account online
Click on Combine files to PDF, then Select Files
Choose one or more files to merge into a single PDF
Click Open
Enter a name for your new file
Click and drag file names to rearrange the order
Click Combine
Click Download
If you have several PDF files that you'd like to combine, you would need to use a full version of Adobe Acrobat.
I hope this helps. Please let us know if you have further questions.