Here's a breakdown:
Noun: It refers to the power to have an effect on someone or something.
* Example: "The teacher has a strong influence on her students."
Verb: It means to have an effect on someone or something.
* Example: "The music influenced his decision."
Adjective: It means having the power to influence.
* Example: "The influential CEO was able to secure the deal."
There is no adverb form of "influence."
Let me know if you want examples of how "influence" is used in a sentence!