To record your expenses, you need to create contacts first for each supplier or create one that indicates an expense type. For example, Electricity bill, Rent or Travel expenses etc.
You can register expenses either as direct payments or as purchase invoices.
From the Cash flow -> Payments menu, you can add direct payments. These transactions simply withdraw funds from the company's cash register and do not participate in the contact's balance (they do not appear on its statement).
To view aggregated results for these transactions, you can create a Payments report (detailed or summary) to see the total amounts you've spent on each expense.
By creating purchase invoices from the Invoicing -> Purchase invoices menu, you get a more detailed picture of these costs and track their payment status or not.
There, you can register your expenses by name on each product line (as items) or by putting a general title (such as office expenses) and proceed with their payment as well, as with regular purchase documents.
Whichever way you choose from the above, you can always group your records by type of expenses by creating tracking categories. Using this feature, you will be able to see useful reports about your expenses and manage your cash flow better!
For more information, visit the related article.