Yes, you can use your microwave without the grill function. Most microwave ovens have multiple cooking modes, including a basic microwave mode that heats food by emitting microwaves. The grill function, on the other hand, uses heating elements located at the top of the microwave cavity to provide direct heat for browning or crisping the food.
If your microwave has a separate grill function, you can simply choose not to use it and operate the microwave in regular microwave mode. This mode is typically indicated by a symbol of a microwave on the control panel. You can set the desired power level and cooking time for your food, and the microwave will heat it using microwaves only.
Keep in mind that without the grill function, your microwave will not be able to achieve the same level of browning or crisping on the surface of the food. However, it will still effectively cook or heat your food using microwave energy.