1. An electronic signature method implemented at an electronic signature application server device, the method comprising: receiving, by the electronic signature application server device, from a document sender, a document containing a fixed document term and a variable document term, wherein the document sender has indicated that a document recipient is not allowed to modify the fixed document term, while the variable document term is associated with a parameter that can be set by the document recipient; receiving, by the electronic signature application server device, from the document sender, a condition on the variable document term, wherein satisfaction of the condition depends on the parameter set by the document recipient; defining, by the electronic signature application server device, a recipient's signature block at a first location in the document that is configured to receive a signature of the document recipient; defining, by the electronic signature application server device, an automatic signature block at a second location in the document that is configured to receive an automatically generated electronic signature authorized by the document sender; sending the document from the electronic signature application server device to the document recipient; receiving, by the electronic signature application server device, from the document recipient, the document, wherein the document received from the document recipient includes the signature of the document recipient positioned in the recipient's signature block; making a first determination, by the electronic signature application server device, and after the document is received from the document recipient, that the fixed document term has not been modified from its state when the document was sent to the document recipient; making a second determination, by the electronic signature application server device, and after the document is received from the document recipient, that the parameter set by the document recipient satisfies the condition; in response to making the first and second determinations, applying, by the electronic signature application server device, the automatically generated electronic signature to the automatic signature block without user intervention; and transmitting the document that includes both the signature of the document recipient and the automatically generated electronic signature authorized by the document sender, from the electronic signature application server device to the document sender.