EU commission response on contractual form of data processing agreements

“The GDPR further provides that such contract or legal act shall be in writing, including in electronic form. [..] In principle, automated contract processes are lawful. It is not necessary to append an electronic signature to contracts for them to have legal effects. E-signatures are one of several means to prove their conclusion and terms.[..]”

Full text:
http://www.europarl.europa.eu/sides/getAllAnswers.do?reference=E-2018-003163&language=EN