What it is for
A PDF keeps several pictures together as one file that opens the same on every device and prints page by page. It is the usual way to send a photographed contract, an ID in front and back, homework pages, receipts or a set of screenshots – one attachment instead of fifteen.
How the PDF is made
Every picture becomes one page, in the order of the list. The page is the size of the picture at 150 dots per inch: nothing is stretched to fit a paper size, nothing is cropped, and no white borders are added. Photos taken on a phone are turned the right way up using the orientation the camera recorded, so a page shot in portrait does not end up lying on its side.
Transparent PNGs are put on white, and an animated GIF contributes its first frame.
In the bot
Send the photos to the bot – as photos or as files, one by one or several at once. A single menu keeps count as they arrive. When they are all there, tap Make PDF; tap Start over if you sent the wrong ones. The PDF comes back as a document in the chat, ready to forward.
The other way round
Have a PDF and need its pages as pictures – to post them, or to send one page? Use PDF to image. To turn a voice note into a normal audio file, see voice to MP3.