1, that is, the goods have arrived, but the invoice has not arrived yet. What should we do when taking stock of the quantity of purchased goods? Should we follow the invoice or the actual quantity?

The invoice hasn't arrived yet, and the valuation record is needed, so it should be calculated according to the actual quantity.

The goods have been delivered, but the invoice has not been sent to the customer. When counting the issue quantity of inventory, is it based on invoice or actual quantity?

There is an item in the VAT report called "Sales Not Accounted", which can be filled in if it is not accounted for. Therefore, it is still necessary to count according to the actual sales volume.

Sometimes suppliers will give us higher invoices, that is, we all know what the price is, but they overpaid when invoicing. So when we count the inventory, is the price according to the agreed price or the invoice price?

It should be recorded according to the invoice price, and there can be no mistakes in the book.