Hey chauncie129,
You sure can! This article shows you what you can manage on your Apple ID: Manage your Apple ID. You’ll find the link to the Apple ID site near the top of second section.
Once you’re signed in, select “Personal Information” on the left. While you’re there, review the article again and see if anything else needs some updating as well.
If you're referring to changing your actual iCloud email address, this wouldn't be possible, but you could create an email alias for iCloud Mail so that you would still receive emails sent to the old address. You would also be able to provide the email alias and it would receive the emails in your current account. Here are instructions for that: Add and manage email aliases for iCloud Mail on iCloud.com - Apple Support
Feel free to get back to us with any questions or problems you may have.
All the best.