In the Context Pane on the right under the "text" tab click on the "plus" next to the bold italic and underline option and it will give you the superscript option among other text-related options.

I have found the answer in another post...

Thanks for sharing Ana!

I also need to add a superscript but I'm not finding the Context Pane?

Hey Michelle

Thanks for posting in the Lucid Community and keeping this conversation going! You can add a superscript to your text using the Text Options button within the top toolbar. I have included a screenshot that should help out along the way. 

We always love to see how creative our users get while using Lucidchart--feel free to post pictures (if you'd like) of your project to let us and others celebrate what you're working on. Cheers!

Ah ha that's where it was hiding. Thank so much Phillip!! You Rock!

No problem Michelle! Please reach out in the Community anytime with questions or to show off your hard work! 

Sorry for digging up an old thread but I couldn’t find the option for superscript and subscript in the menus. I’m currently a free user.

Hi ​@jklucid, thank you for continuing this post! It looks like you’re editing your diagram in Lucidspark. If you’d like more text formatting options, I recommend switching over to edit in Lucidchart using Universal Canvas. From there, you should be find the options for superscript and subscript in the toolbar at the top of the editor. I’ll share an updated screenshot below: 

I hope this helps! Feel free to let me know if you have any trouble finding these options, or if you have any questions.