Under Section 168 of the Companies Act, 2013, a director’s resignation becomes effective on the date the company receives the resignation notice, unless the notice specifies a later effective date. This means that once the director submits his resignation in writing to the company, his office is considered vacated from the receipt date (or the date stated in the notice) regardless of whether the company subsequently communicates the resignation to the Registrar of Companies.

For instance, if a director submits his resignation via email or physical notice on April 1, and no later date is mentioned, his resignation is effective from April 1. If a later effective date is mentioned in the notice, then his resignation will take effect on that specified date.