Eagle lets you upload offmarket listing to portals once sold, so as to make your sale visible online within each of the portal's sold section.
It is recommended that you check with the portals first to determine whether or not each of them charge for uploading sold (and not active) listings to their portal.
If you'd still like to proceed, please follow the below steps:
Add the off-market listing in DRAFT status.
Change the status to Sold (bypassing the usual Active status).
Upload the listing with sold status to portals as usual.