An AI summary notes...
"Based on current resources and tutorials covering PicoPDF through August 2025, PicoPDF PDF Editor does not support adding transition effects—such as Fade, Split, Blinds, or any animated transitions—between PDF pages. The core features allow editing, splitting, cropping, and rearranging pages, but there are no options for page transitions or interactive effects between pages in PDF documents created or edited in PicoPDF.
Transitions such as Fade or Split are available in slideshow and video editing programs by NCH Software, but not in PicoPDF."
This might be of interest.