Wher do you put 'Urgent' or 'Personal' in a letter layout?

Is there any consistent appraoch to where you should put the words 'Urgent' or 'Personal' in a letter layout?

Should it be the first thing (i.e. above the address) or after the Date?

[Anglika]

"Personal" should be put on the envelope to ensure that the recipient opens it him/herself.

You can insert this sort of information above the recipient's name and address at the start of the letter:

Confidential/Private/Urgent

Mr. Joe Bloggs,
Managing Director
xxxxxx