How is it possible to stop negative selling? It means if the product balance is 0 or less than the quantity sold, a warning will be given. Not being sold
A low or negative stock warning is currently an idea for improvement. See this topic:
However, I don’t think stopping the sale will be implemented since it would hurt back-order invoicing, which is legally required in some countries.
The meaning of your question is not clear, @Mina. If you are asking how selling of items showing negative quantities on hand can be stopped, @Ealfardan has answered you. If you are asking how you can prevent items from becoming negative in the first place, you must purchase more of the item before selling it.