“Without Prejudice” means that you are sending a communication in an honest attempt to compromise a matter, in which you might make a concession (either expressly or implicitly) to the other side that cannot be later put into evidence in Court.
Where do I put the words "without prejudice" on a document or email? There are no rules about this but generally, at the top of any document or in the subject line etc - so that it is instantly clear to the reader.
The without prejudice (WP) rule will generally prevent statements made in a genuine attempt to settle an existing dispute, whether made in writing or orally, from being put before the court as evidence of admissions against the interests of the party which made them.
The WP rule is to encourage settlement discussions without parties weakening their position in the formal dispute. Basically, if this rule applies, people can speak and write openly without fear that what they are saying may be used against them in court or arbitration.
The 'without prejudice' label can be attached to any form of communication – letters, emails, phone calls, and meetings – whether online or otherwise. All that is required is that one or both parties state that the communication is 'without prejudice' before the communication occurs.
The 'without prejudice' privilege means parties to a dispute can make concessions and promises without fear that their words will be used later in court.
Dismissal without prejudice means that the judge dismissed the plaintiff's or prosecutor's case without damaging their right to have their matter heard in court later. A prosecutor may ask to withdraw the case against a person to have more time to make a case stronger, find more evidence or question other witnesses.
The purpose and intended effect of the words “without prejudice” is to prohibit a party from using the doctrine of res judicata (from the Latin, “a thing decided”) in any later actions on the subject matter.