Guide
These two tasks sound similar, but they solve different problems. One creates a smaller PDF from the pages you choose. The other trims unwanted pages while keeping the rest of the original file intact.
Split PDF is the better choice when you want only part of a document, such as pages 4-9 from a report, a single appendix, a few invoices, or selected scanned sheets. The output is a new PDF made from the pages you keep.
Remove PDF Pages fits the opposite pattern: you want to keep most of the document, but delete a few unwanted pages like blank scans, duplicates, or outdated attachments. It is a trimming workflow rather than an extraction workflow.
If your question is "which pages should go into the new file?", that is a split workflow. If your question is "which pages should be deleted from this file?", that is a remove-pages workflow. The distinction is mostly about intent.
Split PDF: export only Chapter 2 from a handbook, or only pages 1, 3, and 8 from a long scan. Remove Pages: delete the cover sheet, blank separators, and a duplicate page from a file you otherwise want to keep whole.
Neither task rotates pages, OCRs scanned text, or merges multiple PDFs. If a page is sideways, you need Rotate PDF. If you need several files combined into one, use Merge PDF.
Open Split PDF if you want to export selected pages as a new file. Open Remove PDF Pages if you want to trim a document by deleting pages. For mixed scan orientation, use Rotate PDF.
Read How to extract pages from a PDF for the extraction workflow itself, and How to rotate scanned PDF pages if the pages you want to keep are sideways before export.