“帮”、“帮忙”和“帮助” all means “help” but Grammar is different .
:“帮”and “帮助” are transitive verbs that can take an object.
eg:他经常帮(帮助)我。He often helps me .
“帮助” more use formal occasion or written language. but “帮“use spoken language.
“帮忙”:is a detachable word that can’t take an objeact (person)
eg:他经常帮我的忙。He often hleps me.
“帮忙“ also use spoken language , “帮忙”also can take the action of object.
eg :请你帮忙搬一下椅子。please help me move the chair.