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Firstly it is necessary to create Finance Charge Term and assigned it to all relevant customers.
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Automatically - by batch from Finance Charged Memo menu Process - Create Finance Charge Memo - typically use this to generating finance charge memos for all customers
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Please, see the Example
You can also use Reminders and charge the interest in reminders.
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Create Finance Charge Memo for overdue invoices of customer Adatum Corporation to 31.7.2021
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