帮忙is a noun ,but 帮助can regard as both noun and verb for example 多亏了他帮忙 as a noun 谢谢你的帮助 as a noun 他帮助我们打扫教室 as a verb

帮+忙 is verb+noun ，we don't need any object after 帮忙。 and it can be used like“ 帮忙+verb” 帮忙修一下 帮助 can be as a verb，we still need the object. or a noun, like I NEED SOME HELP.我需要 帮助

1.帮忙 cannot add an object, 我帮忙他。 this sentence is wrong. we can only say: 我帮助他。 so 帮助 can add an object. 2. 帮忙can be add 一个between the two characters, such as 帮了一个忙 or 帮了我一个忙。but, 帮助 cannot be divided, we cannot say 帮了一个助。 If you have any other questions about the two words, just let me know.

normally，according to its useage.帮忙sometimes we use it as colloquial style.帮助as written form. for example: 帮忙递张纸。colloquial style。verb 他在学习上给了我很大的帮助。noun 他帮助我完成了这个案子。verb

帮忙：vreb, use it in informal situation and our oral chinese in daily life mostly. 帮助：verb and noun,use it in formal situation,your thankyou letters or some important party,when you use this word,people will think you are serious and sincere.