This isn't to disagree with anyone else. It is just to share what worked very well for us.
We knew too many people had issues with food, like inlaws who fixed three entirely different breakfasts every morning for their three kids because each would refuse to eat what either of the others would eat. Then they still had to coax the children to eat. Two other families of our inlaws had worse food-related problems with their children. And there were many articles in the media about everything from bulimia to anorexia to obesity from emotional eating.
To avoid all such things, we decided before the kids were old enough to eat solid food that we would not "fight about food". I'm not sure that is the best descriptor but it is the term dh and I used to remind each other if we started to slip.
We served dinner casually (attitude-wise, not casual-vs-formal-wise) and they ate because they were hungry. And, sometimes, because it was what we were doing then (like they played at raking leaves when we raked leaves, or came for a walk when we took a walk, or anything else). If they didn't want to eat something, there was no pressure beyond mild surprise at such a strange concept.
They all ate pretty much everything they were served without much fuss until about middle elementary school age. They are close enough together in age that they were all that age range at the same time.
About that time, they brought significant peer influence home, and I had more time to try different ways of cooking (which didn't always turn out well). They would sometimes decide they didn't like something by looking at it. When that suddenly started happening often, we morphed a little. We required all of us to eat one bite of each thing served at each meal. Then each could decide if he wanted more or not. And, at the first meal of this new norm, we added except one thing of each meal. Because we think it is okay to have some things you don't eat or even to have some things you don't try. And ok to incorporate their input to some degree. It wasn't long before we were back to everyone eating pretty much everything without fuss and that requirement faded away from being irrelevant.
