申す
もうす · mousu · JLPT N4 · verb-godan
-- extra-modest (humble) expression for 言う (いう) --
申 = speak up to a superior; mousu = the humble say (as in moushimasu)
申 means to state or report upward, the same character in 申し込む (to apply). You already know it from introductions: Tanaka to moushimasu = I am called Tanaka. It is 言う lowered a step, used for your own speech only.