When you first open the Mail program on your Mac, you’re prompted to set up an email account. If you already have an existing email account, simply select your email provider from the list shown, such as Gmail, then enter your account information here.
You can keep adding additional email accounts by clicking Mail > Add Account.
Choose an account type, then enter your account information and ensure the Mail checkbox is selected for the account.
If you don't see your provider
If you don’t see your email provider listed here, click Add Other Mail Account and then click Continue.
Enter your name, email address, and email password, and then click Create. In most cases, this will be successful, and Mail will begin receiving new emails that are sent to your usual account.
Troubleshooting
If Mail can’t connect, it will ask you to enter mail settings, including account type (IMAP or POP), mail server address, and the SMTP server address. Get these details from your email account provider.
You can also make use of your Apple ID and the free Apple iCloud account that comes with it. Your Apple ID will give you an iCloud email address (yourname@icloud.com) that you can use to send and receive email.
Choose iCloud from the options when you set up Mail or click Mail > Add Account and choose iCloud, then enter your Apple ID information.
Where does your email live?
Mail works with existing accounts by downloading a copy of your email from these linked accounts and storing a copy locally on your Mac. Your other email accounts will continue storing emails as they normally would, too.
Use a web browser
You can access Mail via a web browser. To do this, type icloud.com into a web browser, then enter your Apple ID and password. Once signed in, choose the Mail app to access your emails.