As per document the Partition option it will parse the partitioned file path and add it as column in destination.

enablePartitionDiscovery - For files that are partitioned, specify whether to parse the partitions from the file path and add them as extra source columns.

How should I configure the partitions and the data load activity to get maximum throughput?

To load the data in faster and efficient way you can try below options:

• Network bandwidth between the source and destination data stores also affect the speed of data transfer.
• You can set the parallelCopies property to indicate the parallelism you want the copy activity to use. Think of this property as the maximum number of threads within the copy activity.

You can refer this document for more information on how to optimize copy activity