Encumbrance & Actual Entries for Expense & Inventory Item

Hi Experts,

Need your advise on the mentioned Subject.

Requirement :

Item:

Expense

PR---PO....Receipt---Invoice---Payment

In the above Flow, when do the Actual Entry gets created for Expense Item

Item:

Inventory

PR---PO....Receipt---Invoice---Payment

In the above Flow, when do the Actual Entry gets created for Inventory Item

Please Advise the Entries in Detail with reference to Actual Entry.

Thanks in Advance