You can notarize something physically or online. In the past, to notarize something, you had to sign it physically in the presence of a notary public. The notary needed to watch you sign the document, and validate your identity to make sure you're authorized to sign the document.
Historically, this meant finding and visiting a notary public in-person: a huge hassle for people who didn't have the ability to take time off work or leave home to find a notary.
Notarize solves this problem. You can now notarize your documents entirely online by connecting with a commissioned eNotary public by live video. Skip the hassle of finding a notary and connect with one online from any iPhone, iPad or computer 24x7.