When you use survey link and proceed with the next button, you are presented with the following view:
Simply click go live now and all you have to do is highlight the link (or click the icon on the right), then copy and paste to invite your respondents. This can be via emails that you're planning to send on your own, via ad banners or as an end_redirect of a web survey (see web surveys).
Warning: your project will have public access with this method, which means that anyone who has the URL can take part in the project.