From Longman Dictionary of Contemporary Englishself-addressedˌself-adˈdressed adjective TCMa self-addressed envelope has the sender’s address on it, so that information can be put in it and sent back to them → sae, SASE
Examples from the Corpus
self-addressed• Letters requiring a personal reply must be accompanied by a stamped self-addressed envelope or a self addressed envelope and international reply coupons.• Specify which countries' sheets you desire, and enclose a self-addressed envelope with sufficient postage attached.• Smyth requests a check and a self-addressed envelope with your request.• I enclose a stamped self-addressed envelope. 