How to Introduce a minimum order value with a delivery charge if the amount of order is less than the MOQ?

You can create order based shipping methods, where you can create a shipping method from say Rs 0 to the MOQ, and can set the shipping charges if the order amount is less than MOQ. It will be automatically applied to the order if user tries to place order below the MOQ.

For example, if you want to apply a shipping charge of Rs 50 if the order is below Rs 500, then create an order based shipping method and the range will be from Rs 0 to Rs 500, if user is placing an order of any amount between Rs 0 to Rs 500, an amount of Rs 50 will be added as the shipping charge.

You can refer shipping methods, for more details about adding shipping methods for different scenario.