This person will not be able to change any of your account settings or chat on your behalf, they’ll only be able to read, send, and delete email messages in your Inbox. This can really come in handy if you want a spouse, coworker, personal assistant or someone else to help you manage your email and send messages on your behalf. You can delegate access to up to 10 users and if you have a Google Apps for Business account, you can specify up to 25 users. Here’s how to do it:
In your Inbox click on the gear icon in the top right corner and go to Settings.
Click on the Accounts tab and go down to the section titled “Grant access to your account.”
Now click on the “Add another account” link at the top of this section.
A window will popup asking for the email address of the Google account holder. As long as the email is valid and within your domain, it will be accepted. Click on the “Next Step” button.
You should see a confirmation message. Click on “send email to grant access” to verify that you indeed want to give this person access.
The delegate will receive a verification email and will need to confirm it. Once confirmed, their email address will show up in the “Grant access to your account” section of the Accounts tab. All done. When that person sends an email from your account, your name will still be displayed along with the delegate’s name (i.e. Your Name (Sent by Delegate)).