Set up product price manually

Hi,

I was trying to set a regular price and a sales price in the product page for the currencies, but it did not allow me to have both. It’s just deleted the sales price when I updated the product page. For some reason, I can only have a regular price displayed. I want to display a sales price as well. Why can’t I have that?

Here’s a screenshot: https://prnt.sc/102wkse