Hello Charline,
At the moment, most businesses use our Projects function as cost centre reporting.
Going to Settings > Organisation > Toggle Features and then turning on Projects will enable this. Note, this will need to be done for all businesses you have access to.
The basis is that you will make a project titled Marketing (example cost centre) and then others for your other departments.
When you do this, you will be able to allocate invoices and bills to those projects. It will save the data to the normal Profit and Loss and then a Project report as well.
To see the projects report, you will need to navigate to Tools > Project > Report. Projects can be toggled on and off. The guide below gives further information about that.
http://www.clearbooks.co.uk/support/guides/projects-settings-2/projects-report-comparison/
Doing these steps will let you set up the cost centres.
PS: as an advanced method for projects, you can use the toggle feature Project Invoice Items. This will break down each item in the invoices and bills to allocate to multiple cost centres instead of a global one.
Please do look at the Clear Books demo account for this as there is dummy data already set up for this.
Vanish