I bought a business. How do we treat the owners investment and owners drawings amount on the balance sheet from previous owners? How does the sale cost get reflected?

Owners investment and drawing should have been rolled up into owners equity before the sale, but you can do it now if you want
debit investment and credit equity for the balance in investment
debit equity and credit drawing for the balance in drawing
but you do not enter it when buying the company

You bought the balance sheet, so each account needs to be entered as your starting balance. If there is a sub account for depreciation, first clear the old company depreciation to the asset.
debit depreciation and credit the asset for the balance in depreciation

Any price you paid over and above the starting balances is goodwill, an asset account that amortizes over 10 years usually.