In reality, it is not possible to change the Gmail address that is associated with your Google account, but you can achieve the same result by creating a new Gmail address and associating it with your original Google account that you use every day. Once you have created your new Gmail account, you will need to configure it so that emails that will be sent to your new address are automatically transferred to your old account. You will also need to change your account settings to be able to send emails from your old account, but with your new username.
Steps
Part 1 of 3: Create the new Gmail address

Step 1. Log out of your checking account
If you are currently signed in to your Gmail account, you will need to sign out before you can continue.
- In your inbox, click on your username icon in the corner of the page, at the top right.
- Click the "Log Out" button on the window that appears to log out of your account.
- Once you log out, you will be automatically redirected to the Gmail home page.

Step 2. Click on “Create an account”
Look for the "Create an Account" button on the Gmail home page. Click this button to be prompted to create a new address.
- If you haven't been automatically redirected to the Gmail home page, you'll need to open that page manually. It can be found at:
- Once you click on the link, you should be taken to the "Create your Google Account" page.

Step 3. Complete the necessary fields
On the "Create your Google account" page, you will be asked to complete a form and indicate the username you want as well as your basic personal data.
- Your username will match your new Gmail address.
- You will also need to provide your first name, last name, password, birthday, country and gender.
- While not essential, you should also provide a cell phone number and secondary verification email address. Thanks to this step, your account will be more secure. If you want, you can use your old Gmail address as a verification address.
- Complete the CAPTCHA, then check the box indicating that you agree to Google's privacy policy and terms of service.

Step 4. Submit your data
Click on the blue "Next step" button at the bottom of the registration form. You will officially create your account and you will be redirected to your Google+ profile.
Since you'll continue to use your old account to sign in to most of Google's services, you don't need to waste time filling out your new account details

Step 5. Complete the procedure
At this point, your new Gmail address has been created. Click on the "Continue to Gmail" button to go to your new inbox.
You have completed the first part of the procedure. Subsequently, you will need to configure your account to redirect emails from your new address to your old account that already existed previously
Part 2 of 3: forward messages from the new address

Step 1. Click on the gear icon
Look at the gear icon located at the top right of your inbox window. Click on this button and then on “Settings” in the menu that appears.
Please note that at this point you should still be signed in to your new Gmail account. You are going to modify the configuration of this account so that all new emails sent to this new address are automatically redirected to your old account

Step 2. Click on the redirect tab
On the "Settings" page, click on the "Redirection and POP / IMAP" link located at the top center of the page.
You will only need to take care of the first section of this tab, called "Redirection". You can now skip the other sections

Step 3. Enter your old address as the redirect address
Look for the button that says "Add a forwarding address." Click this button and write your old Gmail address in the field that appears.
As soon as you confirm that the address is correct, Gmail will send a verification mail to your old address

Step 4. Log in to your old account
Sign out of your new Gmail account, then sign in to your old account. Look for that verification email that was just sent.
The verification message should arrive after a few minutes. If you can't find it in your inbox, check your spam folder

Step 5. Click the verification link
When you open the verification mail, you should see a special verification link. Click on this link to confirm your redirect request.

Step 6. Go back to your new Gmail account
Log out of your old Gmail account once more and log in to your new Gmail account again.
Once you have returned to your new account, navigate to the same page as before. Click on the gear icon, then click "Settings." Click on the "Redirection and POP / IMAP" tab in the default configuration page

Step 7. Configure the redirection
If you haven't already, check the box next to "Forward a copy of incoming e-mail". Select your old Gmail address from the drop-down menu next to this option.
You will also need to specify what Gmail should do with your mail after it has been transferred. You can choose to "Keep a copy of the message in the inbox" or "Archive copy"

Step 8. Save your changes
Scroll down to the bottom of the page and click on the "Save changes" button.
Once you have completed this step, you will be able to receive messages sent to your new address from your old account, effectively changing the email address used to communicate with your old account
Part 3 of 3: Send mails from the new address

Step 1. Log in to your old account
Sign out of your new Gmail account, then sign in to the account you use regularly.
You will need to change the settings of your old account, so that mail you send from it will appear to your recipient as having been sent from the new address

Step 2. Open the configuration page
Click on the gear icon located at the top right of your inbox window. Click "Settings" from the drop-down menu that appears.
The “Settings” page should automatically appear. Once you have arrived at this page, open the “Accounts and Import” tab

Step 3. Add your new "Send Mail To" address
Look for the "Send mail to" section. Click on the link in blue “Add another email address that belongs to you”.
- A popup window "Add another email address that belongs to you" should appear. Enter your new Gmail address in the "Email address" field and check that the "Take into account as an alias" box is checked.
- Click the “Next Step” button, then enter the username and password for your secondary Gmail address.
- Click “Add Account” when you are finished. As soon as you complete this step, Gmail should send a confirmation message to your secondary account.

Step 4. Go to your new account
Log out of your old account and log in to your new address again. Look for the confirmation message in your inbox.
If you don't see the confirmation message in your inbox, check your Junk Email folder

Step 5. Click the confirmation link
Open the email and click the confirmation link that appears in the body of the email.
At this point, both accounts should be connected

Step 6. Log back into your old account
Log out of your secondary account once more and log into your primary account.

Step 7. Create a new mail and change the sender
From the inbox of your main account, click on the "New message" button to write a new mail.
- Click the "From" link in the new message window. A drop-down menu should appear. Click on your new address in this menu to send your mail using your new username.
- Please note that when forwarding a message or replying, you will need to change the address by clicking on the field where the recipients are listed and then clicking "From" in the menu that appears. Choose your new address and write your message as normal.