The Default Document Signer is a user on your account who is a fallback in the case that no other checklist signer/approver was set on an individual checklist. This is a global setting across your whole account. The Default Document Signer will be listed as the default signer, if no other signer is selected, when you add a checklist to a job.

checklist on job

You can change the Default Document Signer on your Account > Settings page. Locate the section labeled 'Onboarding Defaults' and click the 'Change' link next to the 'Default Document Signer' option.

default document signer

Remember that you can always change who Signs/Approves Forms by Default when you edit specific checklist.

checklist approver

Even further, you can also change the Signer/Approver for a specific checklist when you assign a checklist to a job or when you assign a checklist to an individual employee.