Maybe is an Adverb
The word “maybe” has basically the same meaning as the word “perhaps.” It can be placed at the beginning, middle or end of a sentence effectively to indicate that something is neither for certain nor definitely not going to happen.
If you’re unsure whether “maybe” (one word) is what you should be using, try substituting it in the sentence with “perhaps.” If the resulting sentence still makes sense, you should have it right.
Maybe, I’ll go to the mall later. >> Perhaps, I’ll go to the mall later.