(assuming there's no underlying medical reason)
Family mealtimes is probably where you want to get to, but you may have to take the scenic route.
My two (6 and 3) are very different animals when it comes to mealtimes - the 6yo eats pretty much anything you put in front of him and eats it all up pretty quick. He views food as fuel and mealtimes as an interruption to whatever business he's engaged in.
The 3yo would happily sit at the table for 2 hours, blethering away and playing without picking up his fork. He'll eat most things now, and eventually gets there but it can sometimes be a bit of a struggle to get him to finish a meal.
Not all kids want to eat full meals at mealtimes - my 3yo would be far happier if we littered the house with a variety of tapas that he could just pick at when he felt like it.
We started off just battling him at mealtimes - he'd be hungry and grumpy and got objectionable when we tried to persuade him to eat, which quickly became a vicious circle. What we did was to make fruit, raisins, oatcakes etc available to him between meals - not forced on him, but just around if he wanted something small and we made an effort to relax at mealtimes. This resulted in him coming to the table at mealtimes without being starving hungry and as such he was much calmer and ate meals a lot better, and we stopped trying to make him eat it all. Gradually we've eased off on the snacks available and increased his portions at mealtimes and he's fine now.
IMO when they're as young as yours are, its more important that they eat in the first place, rather than eating a structured family meal. Plenty of time to build up to that.
Hope you make some progress, good luck.