why would there be two mail apps in icloud

Hello wysteriadampier,

Thank you for reaching out to Apple Support Communities.

Is it possible you are referring to an alias as outlined here:

"Add and manage email aliases for iCloud Mail on iCloud.com

After you set up a primary iCloud Mail address, you can create up to three @icloud.com email aliases on iCloud.com. After you set up an alias, you can send and receive mail from that alias on iCloud.com and on any device that has Mail turned on in iCloud settings.

If you set up a custom domain with iCloud+, you can change the full name that appears with your custom domain addresses in Mail preferences. You can create and manage your email addresses for that domainon the iCloud+ Features page on iCloud.com.

Note: If you had five MobileMe email aliases when you moved your account to iCloud, you retain the five aliases. However, if you delete one of your five aliases, you can’t create a new one to replace it."

More details can be found here: Add and manage email aliases for iCloud Mail on iCloud.com

If you are not referring to an Alias can you provide a few more details about what exactly you are expernecing?

Cheers!