Deleting Posted Purchase Invoice

Hi NAV Expert

Its my first time handling MS Dynamics NAV - R2 but I was confused that the user can delete posted purchase invoice. Anyone there knows where this set up that can control deleting posted documents?

Thank you!

Change Page/Form Property ‘DeleteAllowed’ is to No. Default it is set to Yes.

If you are using Roles & Permissions, the you can set Delete permissions to No for Posted tables like 122-Purch. Inv. Header and 123-Purch. Inv. Line

Or you can set DeleteAllowed to No in Form 138- Posted Purchase Invoice