More than 250,000 businesses worldwide use DocuSign’s digital transaction management technology to enable legal capture of a digital signature for documents sent to a signer via email or presented on the web. An average of 130,000 unique signers interact with DocuSign every day, including those users who do so from a mobile device. DocuSign says that its customer base doubled in 2016 over 2015. Many documents include a payment component, and DocuSign’s smaller commercial customers asked the company to create technology that would enable them to get documents signed and accept payment at...