No you can't edit PDF files using a text editor like notepad++. Microsoft office word makes pdf files but I think it doesn't read/edit them. My suggestion for you is to download adobe acrobat x pro to edit your pdf files. You don't need to purchase it if you don't want to because there is always a way of getting a software for free. ..
Acrobat Professional is what people normally use to edit PDF documents. There are cheaper and perhaps less clunky alternatives on the market, but their editing features can vary considerably. You'll find some applications may possess advanced image editing features, whereas others may offer better word processing, or support for Unicode and RTL languages, etc.