Use Gmail to access your Google Account

If you use Gmail, you already have a Google Account. With a Google Account, you have access to free Google products like Drive, Docs, Calendar, and more.

To sign in to your Google Account (or any Google product):

Go to the sign in page of the product (for Google Accounts it is myaccount.google.com).
Enter your Gmail username (everything that appears before '@gmail.com').
Enter your password.

Adding Gmail

If you add Gmail to your Google Account, your account's primary username will permanently change to yourusername@gmail.com.

After you add Gmail, the original email address associated with your account will become your alternate email address. If you have verified your original email address before adding Gmail, you will be able to sign in using this email address.

Adding Gmail to an existing Google Account
Go to mail.google.com.
Click Sign up for Gmail.
At the top of the page, click If you already have a Google Account, you can sign in here. You'll be redirected to a sign-in page.
Use your existing Google Account username and password to sign in. On the next page, you'll see a shortened Gmail sign-up form where you can choose your Gmail username

Source by Utente_Test