7. A client computing device associated with a signer, the client computing device comprising: a processor; and memory coupled to the processor and storing instructions that, when executed by the processor, cause the signer's client computing device to perform operations comprising: receiving an electronic signature document from a client computing device associated with a sender, wherein the electronic signature document is received from the client computing device of the sender by the client computing device of the signer independently of an electronic signature service; installing a code module on the signer's client computing device, the code module received from the electronic signature service and configured to transmit the electronic signature document received by an email client of the signer's client computing device to the electronic signature service in response to a first input received from the signer, transmitting, by the signer's client computing device, the received electronic signature document to the electronic signature service for storage in the electronic signature service; accessing, by the singer's client computing device, the electronic signature document stored in the electronic signature service, wherein accessing the electronic signature document includes signing the stored electronic signature document in response to a second input from the signer; and causing, by the signer's client computing device, the electronic signature service to transmit an email attached with a copy of the stored electronic signature document to the client computing device of the sender using the code module.
8. The client computing device associated with the signer of claim 7 , wherein the signer's client computing device accesses the electronic signature document via a Web browser executing on the signer's client computing device.