These options are only available for SeamlessDocs, as WebForms cannot have multiple signers.
How to access Add Request Attachments
You will go to the edit view of your SeamlessDoc (uploaded PDF) and click on the Add Ons tab to select Add Request Attachments. A pop up window will appear and you will be able to toggle on the option to Enable Attachments as well as name your requested attachment and add an optional description.
How to Assign an Attachment
After customizing your requested attachment, you will see the option to assign the attachment to the preparer (this option will always show on any SeamlessDocs (uploaded PDFs), any signer or approver in your workflow. You can only assign one submitter (preparer, signer or approver) per attachment. If you make an attachment required and do not assign anyone, the preparer will have the option to upload, but the first signer will be required to upload in order to submit.
How to add a Reviewer to an Attachment
Right below the option to assign someone to the attachment, you will see the option to add a Reviewer. You can add as many/all later signers or approvers as Reviewers for your attachment by holding down the shift or command key on your keyboard. You must assign a field to a signer in order to add a reviewer.
Why add a Reviewer to an Attachment?
If you would like a later signer to review an uploaded attachment before signing and submitting the form then you must add a reviewer.
NOTE: A user cannot be both a signer and a reviewer of the same attachment. You will want to create separate Attachments for each signer.