how to make a balancesheet include stock as a profit
balance sheet and P&L are not the same.
a stock is an asset to the business and not profit. only the revenue generated from an asset is your profit.
It is not clear what you are referring to. Do you mean inventory? If so, read the three-part Guide on inventory management beginning here: https://www.manager.io/guides/11111. Or do you mean shares in a company owned as an investment?