How would i record if my labours buy item from me in cash or against salary ?
I assume you mean laborers (your workers), not labours.
If they buy from you in cash, just enter a receipt. See the Guide: Make cash sales (sell without sales invoices) | Manager.
If you want to handle their payments via payroll, there are several options. These have been extensively discussed in other forum topics over the years. Please search for them.