Humid!!!
 

What is the best way to create humidity in a small house, where u can't control the exact specifications (like temp) of a certain room? Help please.

There are humidifiers one can run for a room. Many herp enclosures can have humidity raised individually, providing a more exact match for inhabitants.
In my opinion raising humidity significantly in an entire house (not a dedicated herp building) is not a great idea, it can lead to mold growth, and interior condensation over a long period can cause rot and structural damage.

Agree with Lucille, especially on the rotting your house out part.

If you give details about what you're trying to do exactly, more and better options would likely present themselves. What species are you intending to keep, in what sort of enclosure (size, design, materials), and what temp and RH are you trying to achieve? Are you trying to adjust the RH in the whole house, or just one room, or just one enclosure?