For licenses purchased after November 2nd, 2015 customers no longer receive a license key to activate the software.
When you purchase a personal subscription or are assigned a commercial subscription by your organization, you'll be sent an email prompting you to create a JetBrains Account that becomes connected with the license.
Once you've completed your JetBrains Account signup, you can activate the software with your JetBrains Account username/password.
However, you are also provided with an offline activation code in case you need to use software with no Internet connection available. You can retrieve the offline activation code in the license management section of your JetBrains Account, for the license that is assigned to you.