Dry mount on a Acid-Free Mounting Board. Can be done at a frame-shop. Make sure it's a heat process with dry mount tissue and not spray-mounting which could damage the art.Also your pastel needs to be fixed properly before hand. Never use hairspray regardless of ridiculous posts on the net that say it's fine. It will cause the work to yellow and rot in a few years.Fixing may be complicated by the fact that you've used marker [which may have an alcohol base.] Text fixative on a separate paper to which the same marker has been applied and dry for same period of time first.Here are links. Dry mount: [link] Fixing Pastel: [link] Interesting piece.