Step 1: Read the question.
Under Section 105 of the BNSS, 2023, what is now a mandatory requirement for police search and seizure.
Step 2: Understand the reform.
The BNSS, 2023 brings technology into investigations. It aims to make searches more transparent and accountable.
Step 3: Learn the requirement.
Section 105 requires the whole search and seizure process to be recorded by audio-video electronic means. This creates reliable evidence.
Step 4: Understand the benefit.
Recording protects the rights of citizens, ensures fairness, and gives strong evidentiary value at trial. It reduces claims of tampering.
Step 5: Check the other options.
The BNSS does not require five local witnesses. It does not require a Judicial Magistrate present at every search. It does not need a signed confession from the occupant.
Step 6: Final answer.
So the mandatory requirement is audio-video recording of the search and seizure.
\[ \boxed{\text{The documentation of the entire search and seizure process via audio-video electronic recording}} \]