Before you start, you need to first create an email in cPanel ( Guide : Creating Email Address in cPanel | Host Koala ), and you will also need to know your Email server hostname.
For Email Server Hostname, you can find it via Your client page, by clicking on your service tab like shown below :
And it will reveal your POP email server ( In red box shown below )
We will need this value in steps 6 and 7
STEP 1 : Log into your GMAIL Account
STEP 2 : Click on the settings icon located at the top right of your gmail page ( Beside your google account avatar )
STEP 3 : Click on See All Settings
STEP 4 : Click on Accounts and Import and then click Add a Mail Account
STEP 5 : Input your email ( For this example, we are using email@example.com )
STEP 6 : Enter your username/password ( The username/password of the email you created previously in cPanel ). For POP Server, use the email server hostname. Select Port 995 and tick the Always use SSL option as well as the Label incoming messages. Click on add account.
STEP 7 : Next, if you want to allow GMAIL to send out emails for you, you need to click on Yes, I want to be able to send mail as XXX@XXX.XXX and click Next
STEP 8 : Enter your desired name and click Next Step
STEP 9 : Enter your username/password ( The username/password of the email you created previously in cPanel ). For SMTP Server, use the email server hostname. Select Port 465 and tick the Secured Connection via SSL option and click Add account
STEP 10: Check your email in cPanel ( via cPanel -> Email Accounts -> Check Email ). Input the verification code sent to that email in the textbox shown, and click Verify.
And you're done !