Who knows, the concepts of Mr./Ms. may soon become quaint and archaic as gender-fluid awareness increases. I don’t know what is done in these situations, maybe we will scrap all titles except for honorifics such as Dr. and Rev.?
^ When was the last time you saw a piece of mail addressed to “Master” [last name]?
But Master indicted a young male, not specifically an unmarried male (if that’s where you’re going). An unmarried grown man would still be Mr.
I scrolled through a list of teachers I know at our school and I’m unaware of any female married teachers who didn’t change their name - even if it’s a second marriage. I don’t know all of the more recent teachers personally though, esp those outside of my own fields of math/science.
It’s common for ladies to be addressed as Mrs “Jane” lastname when talking about them or with mail addressed to them. Mail sometimes comes to Mrs “James” lastname, but I haven’t heard anyone verbally announced or talked about that way in a long time.
At school, the handful of times my dh came in for one reason or another he tells kids - or anyone - he’s the “Mr” of us. He’s essentially my “Plus One” there I suppose.
When I’m in the south I often still hear ladies addressed as Miss. I don’t hear that where I live. In the south I think even some of the “Miss” ladies are married TBH, but I don’t ask. I’m not in schools there - just traveling or with relatives. The south still uses Ma’am and Sir fairly frequently too. It’s far more rare elsewhere, esp from kids to adults (vs service or professional settings).
I have the same name I was given at birth and I still had to get a Real ID license. My oldest has the name she was given at birth and she had to get a REAL ID. My younger daughter has an entirely different name (she’s adopted) and we all followed the same process - show a passport with name on it. I think I had to sign for their licenses and I had to produce a piece of first class mail for mine.
That passport is golden. Get one with the right name on it.
If people are being formal, I’m referred to by Mrs., Ms., and Dr., depending on who I’m around, and all of them are fine with me. My kids’ friends use either Ms. or Mrs., and that’s fine. Ditto for schools and work things where they don’t know about my PhD. Actually, I don’t always reveal my PhD in all work settings (believe it or not, it’s sometimes a liability, as some people think PhDs are too theoretical and have fewer hands on skills and/or common sense…), but at work, almost everything is 1st name anyway. Only my closest co-workers will call me Dr. Last name, and when they do, it’s normally because the want and respect my technical opinion…
I think on my grandmother’s cruise registration I once saw the options for titling oneself “Princess” or “Admiral” too. 
The one thing I dislike is when a service provider, waitstaff, etc. call me “Miss” because they erroneously think people might like to be considered “young” instead of calling me “Ma’am” or just talking without a title at all.
I’m otherwise fine with Ms. or Mrs. in casual interactions. I prefer Ms. for many cultural reasons and for a year’s worth of what students call me, I announce “Ms.” as my preference.
“Only my closest co-workers will call me Dr. Last name, and when they do, it’s normally because the want and respect my technical opinion…”
About the only time I get called Dr. Last Name is on mail or phone calls from my alma mater where I earned my PhD - when they want a donation.
About the only other time would be if I am being introduced as a guest speaker or outside expert somewhere.
PhDs are quite common in my field - approaching 50% of the staff in some departments. But in my experience, even in fairly formal companies, scientists with PhDs are almost always called by their first names along with everybody else. Over the years I have run into 1 or 2 PhDs who insisted that others call them “Dr.____”, and they are universally regarded as stuck up.
I’m more in a manufacturing environment, and I’m the only PhD at my plant, and yes, we consider it pretentious when the R & D scientists and engineers from corporate insist on being called Dr. When my co-workers refer to me as Dr., it’s almost jokingly–hard to explain, but it’s funny and kind of more of a nickname…
But back on track, no one at work has ever really asked or cared if I changed my name when I married or not…
“But back on track, no one at work has ever really asked or cared if I changed my name when I married or not…”
Nor should they.