Using data frame analytics requires source data to be structured as a two dimensional "tabular" data structure, in other words a data frame. Transforms enable you to create data frames which can be used as the source for data frame analytics.
This functionality is in technical preview and may be changed or removed in a future release. Elastic will apply best effort to fix any issues, but features in technical preview are not subject to the support SLA of official GA features.
Data frame analytics enable you to perform different analyses of your data and annotate it with the results.