"Mrs. is the shortened version of the honorific applied to a married woman - "Missus".
Traditionally a single woman would be referred to as "Miss.", however in modern times the neutral honorific "Ms." may be used for both married and unmarried women.
I would address it to Mr and Mrs David Keys. For the salutation I would use Dear Mr and Mrs Keys.
Yes. It would be appropriate to say "Mr. and Mrs. Smith" for example.
If she is married.
Always use Ms. in the exact same way you would use Mr., unless the woman has specified another title such as Miss or Mrs.
That is a matter of preference for the woman. Many would use Mrs. to indicate that she had been married to the father of the child.
Always use Ms. in the exact same way you would use Mr., unless the woman has specified another title such as Miss or Mrs.
"Ms." is an intended title for all women, regardless of marital status. "Mrs." is intended for married women. So yes, you can use "Ms." for someone who is married and would also be called a "Mrs."
Mrs Robert Smith is appropriate, but more so would be to use her first name, such as: Mrs. Julia McGillicutty
it should be Ms.
I would call her by miss or mrs and use her first name. it works for me.
It would be more customary to use either "Frank and Nancy Jones" or "Mr. and Mrs. Frank Jones".
Always use Ms. in the exact same way you would use Mr., unless the woman has specified another title such as Miss or Mrs.