Ensure that you have administrative access for Google AdWords as well as editing permission for Google Analytics
Sign into your AdWords account > Click the gear button > Select Linked accounts
Locate Google Analytics > Click View details
You will see a list of Google Analytics properties to which you have access to here > Click "Set up link" for the property you want to link to AdWords.
A pop up like the one below will appear > Select Import Site Metrics > Click Save
Congratulations! You have now linked up your Google Adwords and Google Analytics.
Connect with other products like Google Analytics and more.