Can someone tell me what "accrual" is in accounting and what it is for? Tkx.

An accural is for accounting for expenses in the month that they were incurred. For example if I spend $100 on a plumbing service in September but I won't receive the bill/invoice until October but I want the expense in September's financials, then I would accrue the expense in September and then when I actually pay in October, I will pay and reverse the accrual