Google Docs' drawing tool can be used to add a signature to your document, but it's more secure to use an add-on, like DocuSign or HelloSign.

How to add a digital signature to your documents No need to print a document, sign it and scan again. Use these tools and websites to add your digital signatures in a few simple steps.

Google announced a beta of eSignature for Google Docs and Google Drive today, enabling users to capture electronic signatures in documents.