The Check Payment module has no settings and enabling it does not create a tab. Many merchants use it for testing purposes or for select business to business customers from whom they will accept checks or purchase orders.
Check Payment is an off-line module, which means that payment is received well after the order is created. The workflow typically looks like this:
There is a simple method you can use to track payments that were made by check:
With this filter you can see check/purchase orders that were created but which have not been marked as Captured. Filtering orders this way is also useful for any other payment method that uses automatic authorization and manual capture.