This article provides a step-by-step guide on how to attach files to a PDF using Adobe Reader DC on Windows, Mac, or Android.
Steps

Open the PDF file in Adobe Reader. To do this, launch the red Adobe Reader app with the white stylized letter A icon. Then, click on File from the top menu bar, followed by Open..., select the PDF document you want to attach files to, and click Open.
- If you don’t have Adobe Reader, you can download it for free from https://get.adobe.com/reader for use on Windows, Mac, or Android.

Click on Tools (Tools). This option is located at the top left corner of the window.

Click on Comment (Comment). You’ll see the text input box located in the top-left corner of the window.

Click on the paperclip icon next to the "+" in the toolbar at the top of the window.

Click on Attach File (Attach File). The cursor will change to a paperclip icon.

Click on the location where you want to insert the attached file in the PDF document.

Find the file you want to attach and click Select (Select).

Customize the display of the attached file. Simply use the dialog box to adjust the color and visibility of the icon representing the attached file within the PDF document.

Click on OK.

Click on File in the menu bar and then select Save from the displayed options. The attached file is now saved in the PDF document.
