To download the N-648 immigration form, go to the home page of U.S. Citizenship and Immigration Services, located at Uscis.gov. On the home page, click on Forms. Scroll to the bottom of the Forms page and click on Form N-648, Medical Certification for Disability Exceptions, which is the last form listed on the page. Then click on Form N-648 to open a PDF copy of the form that you can then download by right-clicking the page and selecting Download File.
If you are browsing the Internet with Safari on a Mac computer, when you right-click the PDF copy of Form N-648 select Open in Preview to open the file offline. Alternatively, hover over the bottom of the browser window with your mouse pointer until you see four translucent icons appear. Click on the rightmost icon, a computer with an arrow pointing down, to download the file directly to your Downloads folder.
To view PDFs in your browser window you need to have installed Adobe Flash Player. First, ensure that you disable all pop-up blockers. Then, visit the Adobe website at Adobe.com, click on Menu, and select Adobe Flash Player. This brings you to the download page for the software. Click on Install Now to download the installation file to your computer. Click on the file and follow the prompts to install the software, then follow the instructions here to download Form N-648.