請問有冇人知，英文信件中的稱呼Ms 和 Miss 有冇分別或

Ms.
1.
女士(用於婚姻狀況不明或不願提及婚姻狀況之女性的
姓或姓名之前)
2.
a title of respect prefixed to a woman's name or position: unlike Miss or Mrs., it does not depend upon or indicate her marital status.
3.
a title prefixed to a mock surnamethat is used to represent possession of a particular attribute, identity, etc., esp. in an idealized or excessive way: Ms. Cooperation.

Miss

1.
(用于姓名或姓之前, 尤指對未婚女子的稱呼) 女士, 小姐
Miss Brown is a popular teacher.
2.
(用于選美會等, 加于國名或地區名之前) ...小姐, ...皇后
Her daughter was chosen as Miss Hong Kong six years ago.

Women are getting more independent in these modern days so "Miss" means the woman is single, and;
Ms." could be a single woman or a married woman. If you were to send a letter to someone and you weren't sure if the woman was married or not you would put "Ms. xxx." For divorced woman-use also "Ms".