Heritage of Power books 1-4:
Dragon Storm
Revelations
Origins
Unraveled
By Lindsay Buroker.
Set in a fantasy-ish world with a touch of steampunk, what magic existed was the result of humans cross-breeding with dragons. (The dragons can shapeshift into anything, so there are lots of half-dragon animals and people around.)
The series wasn't deep and meaningful, but not everything has to be. Each book was fast-paced, had enough action to be interesting but not so much I wanted to skim, and the characters were all good from major to minor.
One of the two main characters is Trip. Half-dragon, but living in a part of the world where having magic would get you burned for being a witch, so he had to hide it.
The other is Rysha. Noble-born, all she wants to do is earn a place in the elite unit of the military (which of course her family doesn't approve of at all). She wears glasses, and I suspect the author must as well, because the issues around fighting and traveling through a fantasy world while wearing glasses were so realistic. Nothing like being in a sword fight and having them knocked off your face!
The two main characters (along with some others) were sent on various missions by their king.
This is the author's second series set in the same world, and it showed. The world was nicely fleshed out and felt real.
I had thought the series was books 1-4, but apparently there's a fifth one, so I'm reading that next.