When adding an e-signature document in the Templates section, you're able to choose if the type should be "simple" or "offer".
Simple documents
Simple documents can be sent to candidates at any stage of the pipeline by clicking the three dots icon and choosing "request e-signature". They are best-utilized for things like NDAs (non-disclosure agreements) or other standard contracts that are not job offers.
They can include custom variables.
They cannot include the [company_signature] variable or approval workflows.
Offer documents
Offer documents can only be sent to candidates in the Offer stage of the pipeline. Multiple documents can be sent at the same time. For example, you could send the official offer letter and an NDA.
Offers can include custom variables, internal fields, a [company_signature] variable and approval workflows.
The salary entered for the offer document will feed into budget reporting for accounts with Hiring Plan. A special section will appear on the candidate's profile showing the offer details and acceptance status.