Recently charter email has been rebranded the name and now it's known as Spectrum webmail. charter.net domain was kept so that existing clients can use their emails.

Steps to email settings for chater.net?

-Sign up for Spectrum.net services and create a username and password.
-Log in to your Spectrum account.
-Go to the Menu icon in the top left corner of the page and select Manage Account.
-Choose Services >Internet.
-Choose to create an Email Address and create a new username.
-Then select Create Mailbox (it can be something like username@charter.net).
-Enter your Spectrum.net password > Finish.

You’ll receive a confirmation notice that your mailbox has been created. Select Go to Mailbox and use your Spectrum email account

For Complete details, you can visit: https://webcrush.net/charter-email-login/