Refusal of visa

I applied for a Schengen visa via the Spanish embassy. The visa was refused for four reasons:

1. Justification for the purpose and conditions of the intended stay was not provided.
2. You have not provided proof of sufficient means of subsistence, for the duration of the intended stay or for the return to the country of origin or residence, or for the transit to a third country into which you are certain to be admitted, or you are not in a position to acquire such means lawfully.
3. The information submitted regarding the justification for the purpose and conditions of the intended stay was not reliable.
4. Your intention to leave the territory of the member states before the expiry of the visa could not be ascertained.

My question is if I am to appeal, what documentations do I need to provide?

You need to say, what info did you provide. How much $ did you show you earn or have in the bank. Do you earn $ outside of Spain (pension or internet work).

It is impossible to answer your question without more information.