When you receive feedback from multiple participants, each in a different copy of the original PDF file, you may find it helpful to merge these comments into a single PDF file for easier review.
Merging comments is a two step process:
Export comments from each commented file
Import all comments to collate them into a single PDF file
With a commented PDF file open, on the Review tab, in the Review group, click the arrow next to Migrate, and then select Export Comments. The Export Comments dialog appears.
Specify a unique filename and location for the exported comments, and then click Save
Repeat steps 1 and 2 for every commented file
With the original PDF open, on the Review tab, in the Review group, click the arrow next to Migrate, and then select Import Comments. . The Import Comments dialog appears.
Select a comment file to import, and then click Open
Repeat steps 1 and 2 for every comment file