Does the Google Analytics plug-in for WordPress automatically insert the code when you give it the UA string?

I’m very new to using plugins on WordPress. One of them is for Google Analytics and when I tried to activate it, it asked for a UA string. So I registered on Google Analytics and got that string and entered it in the appropriate box back on WordPress. What I’m wondering is if I still have to insert the html code on the template or if its done automatically for me?