Not able to access my emails since I changed my password

You changed what passwords - and where?

If you have changed the email password on your email providers web-servers, you must also change the corresponding password(s) for the email client-accounts on your iPad and iPhone. Account passwords for the native Mail client are accessed and changed here:

Settings > Passwords & Accounts > [Account]

You should note that changing any email passwords on your iPad/iPhone does not change the actual email password used by your email providers email servers. When changing an email password, both the email server and devices that access the account must be updated. To change the email account password, you will need to sign-in to your email providers web-portal - and change the account password.

I hope this clarification is helpful