Yes, signatories play a huge role on the Pulley platform.
You need signatories in order to populate your share certificates with the appropriate signatures.
Signature lines will be left blank on certificates until a signatory has approved and signed for the security.
Share certificates require 2 signatures, from the Primary and Secondary signatory. The Primary and Secondary signatories can be the same person, but the positions must be distinct (e.g. Bob signing as both CEO and Secretary is fine).
Steps on adding a signatory, refer to this help article.
You need signatories in order to access Pulley's e-signing feature.