PLEASE HELP! Meal time is so difficult!

My daughter is a little over 15 months and used to eat whatever we gave her. But lately meal time has become a joke. Food she has liked she refuses to eat or even try. I feel so limited on what I can feed her she is refusing everything. Though sometimes she will eat it later not in her high chair. (Like if I’m snacking on some water melon she will walk over and share with me, but if I give it to her in her high chair she won’t touch it.) I don’t understand what has changed and what to feed her. I am beyond frustrated! Any advice or tips would be so greatly appreciated!