You can get FIM positives from your postmaster or mailpiece design analyst. FIMs are also available on Postal Explorer at pe.usps.com; under “Business Solutions” in the top bar, click on Mailpiece Design.
You can find the templates for your reply mail envelopes on Postal Explorer, as well as options for obtaining FIMs and barcodes, obtaining permit numbers, and payment options; under “Business Solutions” in the top bar, click on Mailpiece Design.