Summoning, Evocation and Invocation
Evocation : It's practically the same thing as Summoning , you are calling upon an entity to manifestitself or its energy, outside your body or circlefor a situation, may it be forlove, protection, knowledge, or healing, which is pretty much the same thing about summoning just different words. you are calling upon an entity to help you on something.
Invocation : It's the same thing as evocation but instead of calling on an entity to manifest itself but instead of it to manifest outside your body or circle, your calling that entity inside your body, it's like a temporary, voluntary possession, whether its a demon, an angel, a god, or even a spirit.
Got the info from exprience and my point of view of the terms.