48 C.F.R. § 332.7002 – Policy.

(a) Contracts shall require the electronic submission of payment requests, except for—
1. (1) Purchases paid for with a Government-wide commercial purchase card; and
2. (2) Classified contracts or purchases when electronic submission and processing of payment requests could compromise classified information or national security.
(b) Where a contract otherwise requires the electronic submission of invoices, the Contracting Officer may authorize alternate procedures only if the Contracting Officer makes a written determination that:
1. (1) The Department of Health and Human Services (HHS) is unable to receive electronic payment requests or provide acceptance electronically;
2. (2) The contractor has demonstrated that electronic submission would be unduly burdensome; or
3. (3) The contractor is in the process of transitioning to electronic submission of payment requests, but needs additional time to complete such transition. Authorizations granted on the basis of this paragraph (b)(3) must specify a date by which the contractor will transition to electronic submission.
(c) Except as provided in paragraphs (a) and (b) of this section, HHS officials shall process electronic payment submissions through the Department of the Treasury Invoice Processing Platform or successor system.
(d) If the requirement for electronic submission of payment requests is waived under paragraph (a)(2) or (b) of this section, the contract or alternate payment authorization, as applicable, shall specify the form and method of payment request submission.