I assume you're talking about Kentico MVC. In such case you need to handle it the same way as you'd do with regular .net: pass either page number or skip/take pair to controller.
Regarding API Document Query has appropriate methods to implement it, e.g.
// Retrieves the second page of size 3 of smartphone pages.
DocumentQuery smartphones = DocumentHelper.GetDocuments("CMS.Smartphone")
You can find more samples @ https://docs.kentico.com/k12/developing-websites/loading-and-displaying-data-on-websites/writing-transformations/reference-transformation-methods