The two Accrual Methods used in Oracle are 'On Line 
Accrual' and 'Period End Accrual'. 
On Line Accrual also called Accrual at Receipt means the 
Accrual Accounting is 
generated by the Receiving Transaction at time of receipt. 
On Line Accrual is used for accruing Inventory Destination 
transactions and in 
a limited way Expense Destination Transactions where there 
is the need to 
perpetually track stock movement. Period End Accrual is the 
recommended method 
for accruing Expense Destination Transactions.

They are two Accrual methods
1 Accrue on Recepit
2 Accre at period end

Accre on receipt means that when a receipt is saved, 
accrual transactions are immeditely recorded and sent to gl 
interface. This is also known as "online" accruals.
Accrue at periond end means that when a receipt is saved, 
the accrual transactions are not immediately recorded and 
sent to gl; instead the accounting entries are generated 
and sent at the end of the month by running the Receipt 
Accrual-Period End process