Item purchase code is automatically generated after you purchase any theme in Themeforest. You can find out what your item purchase code is by following these steps –
1) First of all you must go to your Themeforest Download Section.
2) In this page, you should see list of your purchased items, for example we want to find out Theme item purchase code. To do that we must find theme file in Download section list and then click on the Download button and select the Licence Certificate.
3) After click on Licence Certificate link, it should automatically download licence file, which you must open and search for a row that contains Item Purchase Code: and some random code. (For more information check screenshot below).