Tap the account switcher in the top left corner and you should see the option.
See my comment for a screenshot. I don’t know why I can’t seem to post a screenshot in the body of post. Every time I try it gets removed.
Before saying that the ad-free version is not 19.99, please update your app to the latest version. You will see the new option to only buy lifetime ad-free.
I think people mean regional pricing. for example in Australia this means $34. you can buy Microsoft Office for that price. I love the product and I may spend that but it’s still high.
the latest standalone version outside of 365 is office 2019. can buy it for $29 AUD here: https://shop.winandoffice.com/australia/product/microsoft-office-2019-professional-plus/?gclid=Cj0KCQjwoK2mBhDzARIsADGbjeoYQ-UXlPNcG4flFVZsMCT9EU3h4iE9D4956Pvc7wT6sZCPCAJTu7EaArtBEALw_wcB
but it’s $34 AUD for Sync.