Correct spelling, explanation: this is the form, derived from the verb create which means to make something. In this word there is a silent e that is not pronounced and therefore, forming the noun, e should be removed. Then, the suffix or is added to make the noun, referring to a person that does something like in the words decorator, narrator, and educator. A similar suffix is er but there is no rule that says when these nouns have or ending or when they are spelled with er ending. However, the word comes from Latin as creator with or ending. The word also existed in Old French in the same form and it has survived until today. Therefore, the only correct form is creator, not creater.

Definition of creator:
noun, a person who invents or makes something,
He is the creator of many fantastic shows.
It is logical that God is the Creator of all things.

Phrases with creator:
co-creator – someone who works with others to make something,
Jenny and Will work together and they are co-creators of some innovative products.
content creator – someone who makes entertaining or educational material to be shown to the viewers,
He became a successful content creator and he always knew what interested the audience the most.

Incorrect spelling, explanation: the word creator is a noun, derived from the verb to create where at the end the silent e occurs. This non-syllabic vowel sound is usually removed when new derivations are made. Then, the suffix er or or is added. But in this case, the ending or appears in this noun, meaning doer of something. Besides, the word originated in Latin as creator where there also was the ending or, not er. It means that only creator is spelled correctly, whereas creater is incorrect.