'Cash from debtors' means any income you receive from account customers who you send an invoice to, usually at the end of the month. After they have been sent an invoice but before they pay, they are your debtors. When they pay you, the payment is referred to as Cash from debtors.
Decide whether you will offer account facilities, and if so who will be eligible.
Your account customers - if you have any - might be other galleries or corporate customers that make purchases (perhaps of prints, or maybe original works) from you on a regular basis.
Agree payment terms with your account customers so that there is no confusion as to when invoices should be settled. You might, for example, require all accounts to be settled every month, perhaps by a particular day of the month. Alternatively, you might state on your invoice that payment must be made within, say, 28 days of the invoice date.
Make an estimate of the amount of income you are likely to receive from account customers each month, including VAT. Enter the amount in your cash flow in the month in which the money is due to be received.
Consider what steps you will take to recover any overdue amounts and whether interest will be charged on these.
Your business stationery
Have some invoices printed for your account customers. A good printer will be able to advise you on layout, style and even content. If you are registered for VAT you must include your VAT registration number on your invoices.