Back office payments are entered through the Add a payment form, on a constituent record, or in batch. Back office payments are basically anything that is not entered through a sales method (like Daily, Advance, or Online Sales). 

If a payment is made through the back office, there will be edit options in the Tasks menu on the Payment record. For example, Edit Payment, Edit Original Amount, Change Constituent on Payment, and Delete Payment. If these are missing, that means that the payment is for a Sales Order. 
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If the payment is for a sales order, the application details will be applied directly to the order. 
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