This is my 1st time with a deductible - so I'm not entirely sure how it works. Do I receive a refund for my deductibles? If so, why do I not see it on my final return?

I'm a pizza delivery driver and plan to claim my mileage expenses for the year. I'm just confused as to why that section of the refund isn't appearing when I attempt to finish filing - and don't want to risk losing out on that return if I'm owed it.