A common problem that organizations face is how to gather data from multiple sources, in multiple formats. Then you'd need to move it to one or more data stores. The destination might not be the same type of data store as the source. Often the format is different, or the data needs to be shaped or cleaned before loading it into its final destination.
https://learn.microsoft.com/en-us/azure/architecture/data-guide/relational-data/etl
