You can fill out the passport application form that applies to you right on the State Department website, but there's a catch that throws a lot of people for a loop.
At what seems to be the end of the process, you'll see a pdf preview of the completed application. Depending on your browser, there may be a printer icon available, as dones in Chrome. It won't work. What is on the screen is not actually in pdf format.
What you have to do, which is not explained on the preview, is go back to the form filler application and follow a couple of more steps, which will generate an actual pdf file you can download. That, you can print.
Another catch, however, exists. In some browsers, like Chrome, the pdf printing function does not work 100% properly, and the bottom of the form will be cut off on some printers. That printed form will not be accepted by the passport agency. If that happens, here's what to do:
Tight-click the pdf file on your computer and then click Open with in the pop-up menu. Choose Adobe Reader. You can print from there, and you'll get a complete form on all printers if you check the "Shrink to fit page" option box in the print dialog box.
The form doesn't print property on Macintosh computers, either, from the Chrome browser, but I don't know how to deal with Adobe Reader on a Mac. I'm sure there is a "Shrink to fit page" option there, too.
Now, if you think this is really, really stupid, you're right. The problem is that the bottom line of the form and its border are too close to the bottom of the page for many printers. The form is badly designed, as are IRS tax forms, which have similar problems. The agencies, and browser publishers need to deal with this issue. They haven't. The solution is to use the Adobe Reader app, itself, which offers a method for proper printing.
Typical government idiocy.