Are you using the native Mail app, or the Microsoft Outlook app?
Johanna is showing you how to manage an Outlook email account in the native Mail app. Note, the Outlook app and an outlook account are not the same thing.
From what you are saying, I think you may be using the Microsoft Outlook app with a Comcast account.
If I’m right, the problem you are experienceing is due to the Comcast account being a POP3 type account. These accounts don’t save your email’s status (read, unread, draft, folder) on line. It’s all done by the app on the iPad. When you delete the app (or restore it from a backup) all status is lost, and the account will consider all emails stored on the server as new.
POP3 is an older account type, and does not do when accessed by multiple computers or devices.
You’re best bet is to go to the Comcast site (via the web) and acccess your email account. There should be tools to delete old emails. Once you do that, remove and re-add the account to the iPad.
Better yet, get an IMAP or Exchange account with a third party (Google, Apple, Yahoo, Hotmail, etc.) and start migrating your contacts. You’ll be happier in the long run. These type of accounts are meant to be accessed by multiple devices. All status and emails are maintained on the server so that they are not accidently lost, or accidetnly kept.
Note 1: Outlook and Hotmail are Exchange accounts; Microsoft proprietary. Google, Apple, Yahoo, and most other non-ISP accounts are IMAP. Some ISP’s offer IMAP servers as well as POP3. Check their sites for setup instructions. The cheapskates still use POP3, the aboslute minimum email service; probably just so they can claim it in their ads.
Note 2: In general, it’s not a great idea to use your ISP’s email service as your primary email account, even if it is IMAP or Exchange. If you ever move and have to change ISP’s, or decide you want a different ISP, you’ll lose access to that account. If you’ve used that account as your conatact account for other services, then you’ll also lose things like password reset and other features that require authentication through an email.
It’s best that your primary email account be one you can keep no matter where you move or what provider you choose.
Note 3: While it is counter intuitive, your Apple email address is a standard IMAP account. It will keep working whether you use it with an Apple Device or not.