If you didn't receive it last month, you can't merge it into this month.
The specific amount shall be approved by the tax bureau. Generally speaking, there should be 25 invoices for ordinary machines. If the month is not enough, you can apply to the tax bureau for purchase, so you need to increase the ticket purchase limit first.
In addition, you should mainly buy the invoice version. Generally, the small-scale version is 10000 yuan, and each invoice can only be invoiced at 9999.99 yuan at most.