Post a picture to your gallery so we know what you have on the bike currently:
https://www.bikeforums.net/g/user/587778

Chances are, you have a handlebar with 25.4mm clamp diameter (ie. diameter of the bar where the stem clamps on it). If you have a measuring caliper you can measure that for yourself.

There are roughly 1000 choices of 25.4mm handlebars. Search 25.4mm riser bar on Amazon, Aliexpress or Ebay etc. Like this:
https://www.ebay.com/b/25-4mm-Bicycl...520Bar%7C%2521

Keep in mind that you may have need longer cables if the new handlebars is a lot taller than the existing one.