If you want to merge multiple PDF files into one, there are multiple ways to do that on Windows 11. You can use a free ...

PDFsam (basic), a free, open source, multi-platform software designed to split, merge, extract pages, mix and rotate PDF files. Fixed #569: dragging to the edge of the selection table ...

You can annotate to highlight or comment on different areas. You can also merge, re-arrange, or split PDF files. PDF expert can also convert to and from JPG, PNG, Word, PPT, and Excel files.