That depends a lot on where you are, of course. One starting point would be looking up archives or museums in your neck of the woods and getting in touch with someone among their collections or conservation staff.

Whoever you find there will probably have quite a bit of experience with the issue. If there's local companies they use to that end, they could point you towards them, or they could tell you about how to handle the document safely yourself to digitize it. (The latter's more likely, given the document's relative youth, though depending on its condition you might want to photograph it instead of sticking it through a flatbed scanner in the end.)

They might also give you ideas about how to store it in a way that will keep its condition stable over time.