Page ranges
Type ranges such as 1-3, 4-10 to get one file per range.
Every N pages or single pages
Use a fixed size for regular chunks, or one file per page.
Only a few pages?
If you need just some pages as one new PDF, Extract pages is quicker.
Good to know
To split a PDF into odd and even pages for double-sided printing, or to put scanned odd and even pages back together, see Alternate & mix.
Questions
Is the original file changed?
No. Each part is a new file.
Related: Make a PDF small enough to email · Remove pages from a PDF