Gmail has an attachment size limit of 25 MG, but recently announced a new feature that allows file sharing of up to 10GB using Google Drive. Here’s how it works. First of all, you need to be composing your message in the Gmail’s new compose window, so look for the “Try It Now” button (if you haven’t already switched to it.) The benefit of the new overlay compose window is that you can easily access information in previous messages while you are composing.
Now, click the triangular icon (see image below) to attach a Google drive document. Gmail will check your permissions, and verify that everyone receiving the file has the correct permissions. If not, Gmail will prompt you to correct the permissions.