Prepayments are the opposite of accruals.
With prepayments, an invoice has been received before the period-end but part of the monies owed relates in whole or in part to the next period.
For example, an insurance payment paid semi-annually one month before the period-end. 5/6 (5 of the 6 months you are paying for) of the the total relates to the next period. We must set up a prepayment for 5/6 of that bill to defer it until the next period.
The double-entry for prepayments will be entered during the period-end adjustments.