Pay a fixed monthly tax. If the invoice is issued in a certain month, say 40,000 yuan, assuming the tax rate is 4%,

The tax payable is 40000*4%= 1600 yuan, so the tax paid in the current month should be deducted from the quota.

For example, if the fixed tax is paid to 500 yuan every month, it can be paid to 1600 yuan.

And there is no income next month, you still pay the fixed tax according to 500 yuan.

Audit collection is a case involving income tax.