If you’ve installed Google Webmasters to your site and you want to authorize another person to have access to your account information, do the following:
1) Log in to Google Webmasters at https://www.google.com/webmasters/tools/
2) On the home screen, locate your site
3) Click the “Manage site” button and select “add or remove users”
4) Click “Add new user”
5) Type the email address of the person to whom you want to grant access and select the permission level
6) Click “Add”
All done! That person should then be able to sig on to your Webmasters account to view your site information.