Have you just created an upsell but it isn’t showing? There could be a few reasons why that is.
First off, ensure the global upsell setting is active. This can be found under the main settings panel.
Secondly, are both the lead product and offered upsells in stock or have oversell active? By default, Upsell hides upsells out of stock.
Finally, if all those have been checked then its possible there is a conflict with your theme/app setup. If so, you may need to manually add the snippet to show On Page. If you are on the Pro Plan, we can do this for you.