To download a DS-260 form in PDF format, go to the Visas section of the official U.S. Department of State website, click on the All Forms button in the bottom left corner of the Web page, and find the DS-260 form among the others. After that, click on Preview a Sample DS-260, then after the PDF file opens in a new window, right-click on it, and select Save As. Note that you must have Adobe Reader installed on your computer.
Bear in mind that, according to Travel.State.gov, every visa applicant is required to complete and submit the form online. You can still print out the form and complete it on paper, if you find it more convenient. However, you must then transfer your answer to the online form. Also, when it comes to legal forms such as the DS-260, it's very important to download them from the original source. If you download it from any other source, the form may be altered or out of date.
Travel.State.gov serves as a liaison on visa matters to the Department of Homeland Security and U.S. Embassies abroad. Therefore, make sure that you are on the official website before transferring or filling in the form information online.