After buying, how are fixed assets and inventory accounted for? There is no formal invoice, is it calculated according to the inventory quantity and market price?

Of course. This is called fair value accounting. If there is insurance, you'd better evaluate it. The assessment report is recognized by tax and audit. When the fixed assets are recorded, the market price is multiplied by the quantity and then multiplied by the new rate (the percentage of the old and new degree). When calculating depreciation, the service life should be deducted from the service time.

Your assets are not taxed. The monetary funds obtained by self-employed individuals are subject to 20% personal income tax. The income from the transfer of property, after deducting the original value of the property and reasonable expenses, is the taxable income.