How i can add cheque number in cheque payment option

We can enter the cheque number like the usual way, hello-foodforest.

If the field is grayed out, let's ensure to deselect the Print later option. I've added this screenshot as an example:

Also, if you want to print the cheque, you can take a look at this guide: How to print your cheque?

Let me know if you ever you need help. Keep safe!