This download is an editable PDF that will allow you to add your password to it before you print the file. If you want it to look exactly like the one in the picture, you'll need to be sure you have the free font Bebas. Otherwise, Acrobat will substitute another font for the editable field.
UPDATE: You might notice that the original printable I posted has disappeared, and a new one has been posted in its place. I was a little freaked out when, as I was scrolling though my Pinterest feed, I came a cross another Wi-Fi password printable almost exactly like the one I had created. I knew I had seen the other one before, and it was posted before mine. I'm thinking that it was somewhere in my subconscious when I was designing my original printable (and redesigning it a couple of times), but it was way too similar for me to be comfortable keeping it up. That's why I've redone this printable and posted a new version. I hope you like this one just as well. It's still editable, and you'll still need the Bebas font to make it just like the one in the picture. Thanks for bearing with a little design freakiness.