To enable the 'Cost Centers' menu for user to see, you have to set 'Analytic Accounting' Group Access Right first.

Steps : Settings --> Users & Companies --> Users --> Analytic Accounting

You can now view the 'Cost Centers' menu in the Configuration.

Once you are set with configuration part you can create cost centers to manage your business cost for your different branches.

You can select a cost center in the main Sales Order view, which will automatically populate in all the sales order lines. While the cost center can be manually changed on individual sales order lines.

But if the user changes the cost center in main sale order view it will reset to all sale order lines.

When we create invoice for sale order the cost center set in the sale order will be set in the invoice.

This is how you can select cost center inside purchase order which will be auto populated in all purchase order lines, could be change from purchase lines manually.

But if user changes cost center again in main purchase order view it will reset to all the purchase order lines.

Cost center can be assign for each employee to measure their expense done for their cost center.

Cost center will be auto populated from employee if configured otherwise user can select cost center manually.

Expense cost center is also fetched inside expense report too

Expense Report