Today, married women can choose to be addressed socially and in correspondence in many different ways.
The following are also correct, with the addition of either Mrs. or Ms.:
A married woman who is widowed, divorced, or separated is faced with deciding how to adapt her name to fit the situation. Traditional rules were fairly rigid in this regard, but the women of today enjoy more flexibility.
Not so long ago, a divorced woman replaced her first name with her maiden name as her form of address: Sally Merritt DuPree was known as Mrs. Merritt DuPree. In today's world, including a divorced woman's first name with her title and the last name she uses--Mrs. [or Ms.] Sally DuPree--has simply become the less confusing, more sensible thing to do.
When a woman has been divorced more than once, she drops the previous husband's name and uses her first name with the name of her last husband.