Offices, universities and government portals almost always want documents as PDF, even when what you have is a set of photos. Scanned pages, receipts and identity documents usually arrive as separate images. This tool combines those images into one tidy PDF in the order you choose, which is far easier to submit and to store.
Yes. Phone photos of documents are one of the most common uses for this tool.
The common ones, including JPG and PNG.
It depends on the photos. If the result is too big, compress the images first or run the PDF through the compressor.
Yes, arrange the images before you generate the PDF.