If you are creating documents on Google Drive and you need them to get signed, you can quickly send them directly from the word processor's window.
Once you have the add-on install, proceed to Google Docs and create the document as usual. When you're ready to send it go to
Add-ons -> Signaturit -> Send Document.
A bar will appear on the right side from where you'll be able to edit your content's email.
When you're ready click on Send Document to start the signing process.