Abroad it is used to flavour alcoholic drinks such as Bénédictine , Chartreuse, Vermouth and Dubonnet, and locally the root is used to flavour schnapps (Hvannarótarbrennivín). As a medicine it is most often made into a tisane or a tincture, using leaves, root or seeds. It is also a food plant. Here is one recipe:
Take fresh, young angelica stalks, peel off the outer layer and wash the stalks in cold water. Cut away any spots. Pour hot water over the stalks, then cook them in salted water until they are soft. Drain carefully, and serve with whipped butter. May also be stirred into white sauce and served as a side dish (the recipe book doesn’t say what with).
Disclaimer: I have’t tried it, but if I do I will report back.
P.S. Take a look at the comment below - there are instructions for angelica jam in there that sounds heavenly.