Delegates can:
Send or reply to emails that were sent to you. When they send a message, their email address will show. For example, the sender will show as "sent by xxx@example.com."
Read messages sent to you
Delete messages sent to you
Delegates can’t:
Chat with anyone for you
Change your Gmail password
Access your Other Google Data such as Calendar, Drive, Contacts etc
Delegation settings
At the top right, click Settings > See all settings.
Click Accounts and Import.
In the Grant access to your account section, click Add another account.
Note: Your organization may restrict email delegation. If you don’t see this setting, contact your administrator.
Enter the email address of the person you want to add and click Next Step.
Click Send email to grant access.