I have a few question about how prices for Land and Additions are changed post sale. Say there is a property listed for $975,000. Based on its most recent tax statement it shows

Land : $18,445

Improvements: $80,666.00

1. Does improvements mean the price of the built house?

2. How would the land and improvements change if the property were purchased at the asking price of $975,000

@Gaurav Mehta

What you are looking at are assessor's valuation. Those are used strictly to calculate property taxes. They may or may not have any correlation to the fair market value of the house.

Thanks @Basit Siddiqi for clarifying. Yes that is true that this is based on assessor's valuation and used strictly for Tax Purposes. I am actually thinking of making an offer on an investment property in Opportunity Zone. For the property to qualify as Opportunity Zone Property, I need to spend at least $$ =  (Price Paid - Land Cost).

Still not clear on how and who determines what is the value of land and what is the value of square footage. Is that something an appraiser would do or is there an easy way to determine that.

@Gaurav Mehta

Are you operating as a Qualified Opportunity Fund? If no, you may not be getting the benefit you think are getting.

Use of assessor's valuation of land can help you determine your tax basis in land.
One way to determine tax basis in land is to base it on the allocation of building/land from the assessor's valuation.

@Basit Siddiqi : Yes, I will be setting up an LLC and filling out IRS Form 8996 before I actually make the purchase.

Sorry I am still not clear on what you mentioned about valuation. Like I said, to qualify for Opportunity Zone Property, I need to understand how much I need to spend on improvements and that is something based on Price - Land Value. 

Would the land value be the same based on current tax bill

Does that mean the square footage will increase based on the price I buy it for