Normally, receivables on the statement of cash flows are treated as a part of cash flows from operating activities. I say “normally” since some receivables, those not related to the company’s business, should be part of investing activities. 

The distinction is made based on one’s “operations”. If the receivable arose during normal course of the expected business activities of the company, i.e. through sale of goods or services the company does daily, the cash flow from the receivables is then included within the operating cash flows.

However, if the receivable in fact is related to a loan being given or sale of a property, plant and equipment item or some such, it’s not any more related to daily operations but is more of a one-off deal. As such, should it be a loan receivable and it was given during the reporting period, it’s shown as an outflow of cash under investing activities. Should the receivable arise from a sale of an asset, the amount shown under investing activities is total proceeds from the sale less the receivable outstanding. If you didn’t get paid for the sale of the asset, there’s nothing to show on the statement of cash flows either.

Do have your cash flows accurate means you must understand the sources and the activities specific cash flows relate to.