I like this question because "transformation data" could mean quite few things.
I don't know of any formal definition, perhaps others do but here's my take:
Data format transformation - this is when you need to convert a value from one format to another, e.g., text to numeric. Anaplan provides a variety of functions for this. My favorite page is this one which describes all the transformations possible. I would highly recommend creating a favorite link for this one. I use it a lot.
Calculation Modules - As part of the D.I.S.C.O. methodology "C" stands for calculation. In these modules you can convert data from various dimensions to other dimensions by transforming the data. A good example might be mapping your expense forecasts into their respective general ledger accounts.
Data Hub Output Modules - Data that comes into the data hub is usually one dimensional and needs to be prepped for dimensional output modules to their respective spoke applications. This could also be considered a transform of sorts.
Great question @RahulSahoo . Let's keep the conversation going. Let us know where you found the "transformation data". Perhaps we can glean additional clues as to what it means.
Thanks for the inputs. This was one of the questions that came up while I was appearing for a customer interview for Anaplan implementation. Afterwards, when I searched the same, I found very few info on the same. Only thing I found was something I have attached as a screenshot. So I needed some additional insights on this aspect.