Giving an item modifiers

So how exactly do I give an item a modifier? I created an item generator that generates either armor or weaponry. Each item has a level and a rarity value. How exactly do I code it so that they can have a random amount of modifiers?

For example, armor modifiers can do all of the following:
Health regen mod, armor boost, vitality / intelligence boost, mana regen
Weapon mods can have:
Fire damage, shock dmg, ice dmg, and strength boosts

I have variables that hold all these values so that I can add it to the player stats class. Also, the rarity values go:
Legendary (4), Rare (3), Special (2), Uncommon (1), Common (0)

The more rare it is, the more mods it has and the more effective they are. How do I randomly pick these mods for each item based on rarity?

 

Create an Enum of modifiers and give each Item a List<> of them? Then you could add modifiers to the list at item creation.