Can you mail the signed form to the school? If not, see if you can find someone with a scanner that you can use. Scan the signed page and send them the scanned file by email, or upload the scanned file to their web site, if that's what you mean by doing it online. An office services store like Staples or FedEx Office might be able to scan a document for you.
Be cautious about sending anything with personal information, such as your Social Security number, by email or uploading to a web site. Email is not secure, and the web site might or might not be secure. If you have to email it, encrypt it if possible. Maybe they will accept a copy with the Social Security number blacked out.
