Void Functionality for Journal Entry
This application helps to void the unposted journal entry by using 'Void'.
Key features:
Voided record (payment, journal entry) will be read only.
Voided journal items amount will be zero.
Voided entry will not be taken into any accounting report.
Journal Entries
Displays all Journal entries here.

Posted Journal Entry
When state is 'Posted', User cannot change the journal items.
If User want to change journal items need to unpost entry

Unposted Journal Entry
When state is 'Draft', User can edit the journal items.
After change user can either post or void the journal entries

Voided Journal Entry
User cannot change journal items and unpost entry again, when state is 'Voided'.
It locks the journal entry.
Note
If you get warning like below image, while doing unpost entry

Kindly do below configuration, to unpost your entries.
Accounting --> Configuration --> Accounting --> Journals -->
Select journals from list --> Check 'Allow Cancelling