My IRS account shows that I have a payment every year, what does it mean? I always get a refund and never had to pay

Today I logged on to my IRS account and found that I actually have a "payment history" that shows a few hundred to a few thousand dollars of payment every year. I don't understand this. I withhold way more than needed and I get a tax refund every year. I never had to pay any extra tax. What does the payment mean?