In most cases Bonus shares get trading approval in 6-8 working days . TCS and Infosys bonus get trading approval on 3rd working day the fastest possible …1 day for allotment second day application for listing third day listing .
The prices are adjusted on the ex/record date because from that day onwards the stock starts trading without any corporate action benefit, anyone who purchases shares from the ex/record date onwards isn’t eligible for corporate action.
While anyone who has purchased before the record date is eligible. Companies need time to determine shareholders who are eligible for corporate action benefits. Having record dates helps with this. You can check out this chapter on Varsity to learn more about the concept: Corporate actions and impact on stock prices – Varsity by Zerodha
Plus as @aniln pointed out, companies also need to get approval from exchanges before bonus shares can start trading on exchanges.
if Record date is 06/04/2024 SATURDAY last date to buy WITH BONUS will be 04 april 2024 .YES a trading day before record date purchase make you eligible for corporate action if record date is on working day like 05 april 0r 04 april .