How to get 3 year old to eat more foods?

My daughter is 3 and is the most picky eater I’ve ever seen, she doesn’t like the texture of fruit and refuses to eat vegetables. She has been like this for as long as I can remember. I try sneaking things in however she has eyes like a hawk and somehow discovers the tiniest morsel and refuses to eat the food. I have tried giving her a plate and that’s all she gets, however she will go DAYS refusing to eat anything rather than give in. She hates gummies, I want to get her on vitamins. Is there any kids vitamins I can mix in her water? She hates juice, drinking milk (unless in cereal) - mainly water. Advice? 😅