In general, DataHero works with any data in a tabular format (rows and columns). However, much of the power of DataHero comes from its ability to analyze and process data from its raw form. For this reason, it works best if your data is in the raw form when you upload it.
For example, here is some raw data about coffee production by country (notice that there's an individual entry for each year):
This is what the data might look like if you aggregated it by year (noticed that the dates are now used as column headers instead of having their own Date column):
While you can still upload this data into DataHero and create certain charts, you won't be able to use some of the more powerful date-based functionality within DataHero (which requires dates to have their own dedicated column).