1.14 is end of life and no longer supported.

That being said signatures are either in the Agents profile, or in the Department.

Agent profile
go to Agent panel -> profile
notes: each Agent has to change their signature there is no way to edit other Agents signatures.
Also here in the Agent profile there is a selection box for the Agents Default Signature. You could set this to Department Signature (if set) and then just have everyone use the Department Signature, and have one place to
manage the signatures for each department.

Department
go to Admin panel -> Agents -> Departments
scroll down to Department Signature.