Which is the difference between متشکرم - ممنونم

Salam! Which is the difference between

متشکرم - ممنونم

both of them have the same meaning. no difference between متشکرم and ممنونم

and

بفرمایید - لطفاَ - .خواهش می کنم

these words have different meanings. sometimes you can use one of them instead of another but not always. it depends on the sentence.

please= لطفا

you're welcome= خواهش می کنم

go ahead= بفرمایید

Thank you for your help!

بفرمایید = here you are