> my first steps behind me in scanning pictures and documents, but I
> still feel being quite a baby. Last week I wanted to create a jpg
> file, but I got a pdf file (I don’t know yet why. Maybe I should ask
> Auntie Web)."
If you want to create a jpg file, you should copy the image you want to convert and paste it into your Paint program. Paint is a Windows program that came with your PC if it runs on Windows.
To find Paint:
Alternatively, you can download free software that will convert most image formats, e.g. Converter
The site also lists several other free file conversion software which should let you convert most files from one format to another.