Vegetables are important for your health and in keto it the source of multiple vitamins, minerals, and a source of fibers instead of fruits. Vegetables unlike meat and dairy products contain relatively more carbs. so, you should watch your carb intake carefully to keep your body in ketosis.
To eat vegetables freely in keto you must target vegetables with net carb below 5-gram per 100 gram like zucchini, spinach, lettuce, cucumber, and kale. You can eat as much as you wish from these vegetables. With higher net carb vegetables like pepper, you should watch your intake as you can exceed your carb limit easily.
The root vegetables should be avoided in the keto diet due to its high net carbs like potatoes, sweet potatoes, carrots, and onions. Greens are usually preferred as you can fill up your plate without exceeding your carb limit, also cruciferous vegetables like cauliflowers can be used as a replacement for other higher carb meals like rice.