Flip a PDF page horizontally

Hello

I'm looking for a way to flip a PDF page (this page needs to be printed on a layer that applies to a piece of paper). I see a lot of software capable of rotating. What I need is a "Flip" just like a mirror or a car rearview mirror where you can see the word "Ambulance" readable. I found software that can do it, "IrfanView", but it refuses to save the modification in PDF. It's true that a PDF has multiple sheets, and each sheet can become an image...
Do you know of any free software tool that can perform this operation?
Otherwise, if I save it as JPG, will I have the same proportions (scale) to properly align the layer on the paper?

Thank you for your responses
Best regards