Hi David
Thanks for posting to Lucidchart Community! Unfortunately there isn't a way to separate text into vertical columns. Instead you could drag a Text box from the Standard Shapes Library resize it into a column and place it on top of the shape. You could then copy that text box and make another column. I've attached a GIF below.
We’re very interested in your feedback and committed to continually improving our products. If you’re willing to share, we’d love to hear more details about your use case or what you’d like to see in this experience posted in the Product Feedback section of the community - from here, other users can upvote it and add details of their own.
For more information on how Lucid manages feedback via this community, take a look at this post.
Feel free to reach out if you have any other questions or issues!