Some methods that return lists of Item[] , such as, List Emails support paging.

Endpoints that support paging expect two parameters: pageNum and pageSize.

Page numbers are zero-based.
So if you wanted 10 items per page and wanted to retrieve the first page then you'd set pageNum to 0 and pageSize to 10.
For the second page, set pageNum to 1 and pageSize to 10

Paging is usually optional and you can retrieve all items in a list by either not providing value or setting them to null

Page Numbering

For performance reasons we don't provide a total count.
If the number of items returned is less than the pageSize then you are on the last page.
If however it is equal to the pageSize value then there may or may not be another page available by incrementing the pageNum value.