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Our Workspace email plans are defined by address count and plan storage. These plans are purchased only through our customer support teams. They are eventually being phased out (not near future) in favor of our more full-featured Office 365 plans.
The cPanel email mailbox quota counts toward your account's disk space and file count usage. While you can create up to 500 email addresses, you will need to manage the allocation of space in the account to support that larger quantity. If you are using the email for business, we recommend using the Office 365 for the email storage space and cross-client synchronizing.
While the email plans require different DNS settings (MX Records), the use of webmail and the setups in third-party email clients are similar.
Our customer support team can direct you to the plan that will best suit your needs.