To remove information from your PDF file, open your PDF file. Click on Tools pane and open Protection panel. Now move to the bottom of Protection panel on the Hidden Information section and select Remove Hidden Information. Remove hidden Information panel will open on the left and shows you the results. If you click the file you can see all the different items that are going to be removed. If you don’t want to remove some items then deselect that items here and then click Remove button to apply the removing information action. Acrobat will tell you that what is going to be removed from this document, now click OK. Acrobat will process the action and you can see when it is completed. But changes will not apply until you save the document. If you close you document without saving you will prompt to save or cancel the changes.
Another way to automate removing Hidden Information is action wizard, click on File menu, select Action Wizard, where you can create your own actions or pre-installed actions in Acrobat X. Select Publish Sensitive Document, it allows you to mark reduction, remove hidden information, reduce file size etc.
You can also use Sanitize Document from Protection panel, click on it and it will show you the complete list of removing items. Now click Ok. You will prompt to save the document click Save and it’s done.