Open and close accounting periods to control journal entry and journal posting, as well as compute period– and year–end actual and budget account balances for reporting.
Accounting periods can have one of the following statuses:

1. Never Opened: Journal entry and posting are not allowed. General Ledger assigns this status to any period preceding the first period ever opened in your calendar, or to any period that has been defined, but is not yet future–enterable. You cannot change this period status.
2. Future–Entry: Journal entry is allowed, but posting is not. Your period is not yet open, but falls within the range of future-enterable periods you designated in the Set of Books window. You cannot change this period status without using the concurrent process to open the period.
3. Open: Journal entry and posting allowed.
4. Closed: Journal entry and posting not allowed until accounting period is reopened. Reporting and inquiry allowed.
5. Permanently Closed: Journal entry and posting not allowed. You cannot change this period status. Reporting and inquiry allowed.

You can open new accounting periods, close accounting periods, reopen closed accounting periods, and open an encumbrance year (if you are using encumbrance accounting).
If you are using the secondary tracking segment with the Closing and Translation option enabled, General Ledger processing is affected.
Note: 
1. When you define a new set of books, choose carefully the first accounting period you want to open. Once you open
your first accounting period, General Ledger does not allow you to open prior accounting periods.
Additionally, you cannot translate account balances for the first period ever opened. Therefore, we recommend that you open at least one period prior to the first accounting period in which you wish to enter transactions.
2. If you use Multiple Reporting Currencies, you must open/close accounting periods in your primary set of books and in each of your reporting sets of books.