Difference between Standard Accrual and Standard Cash?

Standard Accrual :
In case of Standard Accrual, Invoice and Payment Accounting will be there.
Reason: Transaction happens in two phases.
1)Order goods and receive goods(Create PO, Create Receipt, Create Invoice and account it)
2)Pay the amount for received goods within due time set by the supplier( Pay the invoice and account it)
Since you are not paying the amount immediately, you need to keep track of the amount needs to pay to the supplier after phase one. You maintain this amount in LiabilityA/C(Cr). After second phase, you debit your LiabilityA/C and credit your CachA/C which shows your cash flow from your organization to the supplier.

Standard Cash:
In case of Standard Cash, only payment accounting will be there.
Reason: While purchasing an item you pay amount immediately to the supplier. So you don't have any debt to the supplier to record. so there is nothing to record in LiabiltyA/C.