Integrating with JIRA - JIRA 6.x Administration Topic - page 359

How it works…
The Google Drive in JIRA integration uses OAuth, where each user needs to first authorize
JIRA to access Google Drive on their behalf; this process is called the OAuth dance .
Once the add-on is installed and configured, there will be a new Link Google Document
field under the More menu that can be seen while viewing issues. Clicking on that field
will present you with a dialog to either browse or search for files stored in Google. You can
then select the files you want to link by ticking the appropriate checkboxes:
After you have selected and linked the files you want, the selected files will be listed under
the Issue Links section. Depending on the file type, you will be able to view, edit, and
download the native Google Drive files, if you have permission.