What foods am I allowed?
As other folks have mentioned at its core IF only restricts when not what.
Obviously it gets a little more complex then that if the goal is weight loss. Ultimately you need to be eating less than before. For some folks just cutting out a meal and after hours snacking is enough for them, and they eat basically the same as before - being careful to keep their other meals as normal sized as before.
On the whole IF does give you more flexibility with food options by pushing all your calories into a smaller window. It’s certainly fine to have some thing you enjoy on occasion.
Depending on where you’re staring from or what your goals are if just restricting time isn’t enough then the next step might be to clean up the diet a bit. More foods cooked from whole ingredients and fewer things from the freezer or fast food.
Some folks count calories some folks don’t. Some folks go for specific restrictions like keto. Experiment around see what works for you and adapt along the way.
One last bit, what you’re eating does still matter. As you push more of your calories into a smaller window it starts becoming more important to consider the nutritional variety. Also, eating more satiating foods like good fats, protein, and fiber can make the fasting portions easier.