Instruments affecting real estate are recorded with the County Clerk's office in the county where the property is located in order to:

Give constructive notice to the world of the interest in a particular parcel of property the instrument purports to create.

Explanation: This is one of the regulations regarding real estate in most parts of the world, the main reason for recording the instruments affecting real estate is to give effective notice to everyone of the interest or information a particular parcel of land wants to create, this ensures that all actions or transactions regarding that land must be done in accordance with the relevant regulations existing in that Country.