Is there any option to add a digital signature to all document pages in a simple manar?
Because right now the only option I can find is entering the signature page by page, or by using foxit.
Mind you I am not talking about digital form but rather about a simple scaned contract.
There's no need to do that. A digital signatures applies to the entire file as a whole, not just to the page where you see it. In fact, it can be applied without any visual representation at all.
This not according to any law. It's according to the technical specifications of a digital signature in a PDF file.
If you have to legally digitally sign each page of a 500-page document it's going to be quite an ordeal, and will very likely cause the document to become unusable or at the very least unstable, since you will have to sign each page separately, which will cause the file-size to balloon exponentially. This is not really feasible.
I suggest you investigate this matter a bit further. Maybe it's allowed in your country (Israel, I'm guessing?) to apply a "wet" signature (such as the image of a hand-written signature) to each page, and then sign it digitally once? That would be much easier to do, and would make more sense.