If you're looking for built drawings in your house, the best place to start is with your local building department. They will have a record of all the permits that have been filed for your property, and they may be able to provide you with copies of the plans that were submitted with those permits. If you're not sure where your local building department is, a quick search online should help you find it.
Another way to find built drawings in your house is to hire an architectural researcher or historian. These professionals can often track down original plans and drawings for houses, even if they've been lost or destroyed over time. However, this option can be quite expensive, so it's worth checking with your local building department first to see if they have what you need.