How can I add expenses?

Hi I have an small coffee shop and some of my providers deliver me in the frontdesk of my shop and I have to pay them right away but I don’t know how can I register that expenses… there is an especific option to do that??? or how can I do that bottom or action

There is an example here http://sambapos.org/wiki/doku.php/en/configuring_cash_transactions_for_v2_users