ipad pro data
I'm thinking about buying an ipad pro, with all the fixtures. However data has always confused me. I understand how the basics of mobile data works, but I am wondering if it is the same for an ipad. I am paying a lot for the pad and the accessories, so its important I know what I would be possibly paying monthly for use of data and how I should go about this.
If I have an ipad pro with cellar data and wifi and 128 GB.
Is the 128 GB just a capacity?
Is this data I can actually use after buying the product?
Would I have to go elsewhere to a device shop and buy a sim card, further paying monthly for data?