Long press on the space that you want it located on, select add widget from the personalize menu. scroll down to select it. It should be associated with My Verizon or called Data something. I don't use that widget or app so I can't remember what it is called on my Thunderbolt.
Check for the MyVerizon app. If you have it, then you should have the widget. If not, then redownload it from the Play Store (link HERE) and then long press on the home screen, click Widget > My Verizon Data and it will pop up.
I personally love this widget. It's so handy! But the redesign is UGLY lol. That's just my 2 cents though. Good luck finding it!