Add a file to the entire PDF as an attachment

1. Click the attachment button on the navigation pane and click Add button in the Attachments panel, or choose Edit > File Attachment.
2. In the File Attachment dialog box, click the Add Files… button. Choose Add Files… or Add Folder… to select the files or folders you want to attach. If choosing Add Files…, in the Open dialog box, you can navigate through your local disk to select local files or click Open from ECM to select files from ECM systems or cloud services, and click Open. 
3. Click OK after adding the desired files.
4. The added document will be displayed in the attachment panel.

Tips:

1. An easy method to add a file attachment to PDFs, you can just drag and drop the file you want to attach to the attachment panel. Foxit PDF Editor will pop up a window to ask you whether to attach the selected file to current PDF document. Click OK to complete the operation. Check “Always attach file when dragging files to the attachment panel” option and the next time the file will be attached directly without this pop-up window.
2. Save the document after adding file attachments, and a red dot appears on the icon of the attachment panel in the navigation pane.