Hope you are doing well.
I assume you are referring to the new UI of Acrobat. Is this how your Acrobat's menu bar looks now?
If yes, then The Acrobat modern viewer now includes the All-Tools panel in the left pane instead of the Discover panel. The All-Tool panel provides a seamless experience that facilitates the easy discovery of Acrobat tools without users having to switch contexts.
Here's how you can change the new modern UI click here
Hope this answers your question.