How do I do this? I am new to Xfinity email and am used to another platform whereby you could designate an email as important.
If you're in the new webmail [appsuite - connect.xfinity.com/appsuite] when you have the Compost window open, click on Options and you can set the Priority for an outgoing message there.
If you're talking about a new email you've received, there isn't any way to mark one as important.
If you want to flag an email you received, you can flag it with a color that would remind you it's important. There's a set color icon in the email, and also on the toolbar. You can click either one, and a menu of color choices will appear. Choose a color, and a flag of that color will appear in the inbox to help the email stand out. You can also choose Color as a sort order, so the flagged emails will be grouped together.