Operating costs refer to the amount your brand spent in the year to conduct operations. It includes operating expenses like utilities, salaries, and travel costs, as well as Costs of Goods Sold (COGS, for product companies) or Cost of Sales (COS, for services firms). https://www.investopedia.com/terms/o/operating-cost.asp
If you are a business service it's likely that most of your operating costs will be salaries.