You can filter your pages by name (alphabetically) or by last modified date. Just click "Name" or "Last Modified" below the category name.
This will automatically show your pages in descending order, but you can change to ascending order by clicking the filter a second time. Click "clear sort" or navigate away from the page once you're done using the filter.
Please Note: when you filter a category, that filtered view will only be visible to you. These views cannot be used to permanently set the order of subcategories and pages. If you'd like to reorder your pages, check out how to do so for both categories and subcategories.