how can i open or download a PD file , do I need some software if yes what ?

Answer 1

You should have Acrobat Reader to be able to view a PDF file. But my suggestion will be to use a software name fox it. It is very lite and fast. The software can be downloaded from

http://www.softpedia.com/get/Office-tools/PDF/Foxit-PDF-Reader.shtml

Answer 2

A PD file? Most file extensions have three letters.

I'm going to assume it's a PDF file. Which means you need Adobe Acrobat Reader.. Luckily it's free. Everyone should get that program, because everyone needs it eventually.

Once Adobe Acrobat READER is installed, just double-click on thee file and it will open up in the reader. If not, then it's not a PDF file after all.

http://www.adobe.com/products/acrobat/readstep2.html

PDF files are used to send documents in such a way that they can't easily be tampered with, and are compressed to save space. It also takes support files, like graphics, and holds it in a single file.

The free reader wont WRITE PDF's but it will READ them.
If you want to write PDF's, I personally use PRIMOPDF, which allows me to hit print in any application that allows for printing, and use the "primo driver" as my Printer. You can use that for free, or pay like $500 and get Adobe Acrobat. The advantage to acrobat is that you can combine even unrelated documents of different types to make a multipaged PDF.

http://www.primopdf.com/