You go to www.verizonwireless.com/renewdiscount, then click on Validate By Email Address(if you have a work email address). Another way is to upload a recent paystub. If you can't do either of those, you can go into your local VZW store and show your paystub to them(if you have a picture id badge you should bring it as well, just in case).
As far as 's post, it depends on the company you work for. It also has to do with the plan you are on. Employers are the ones who have the say on what the discount will consist of, Verizon has no say. Some companies only give you the discount on plans they select. Get in touch with your HR and find out what plan(s) they selected for the discount and while your there, ask them what all the discount includes.
Hope this helps.