The Speaker of the Lok Sabha may resign his office by writing, addressed to the

According to Article 94 of the Constitution of India, the Speaker of the Lok Sabha may resign from office by writing under his hand addressed to the Deputy Speaker [1]. Conversely, the Deputy Speaker may resign by addressing the resignation letter to the Speaker. The Speaker is elected by the Lok Sabha from among its members and usually remains in office for the duration of the House. However, the office can be vacated earlier if the Speaker ceases to be a member of the Lok Sabha, resigns, or is removed by a resolution passed by an effective majority of the House after a 14-day notice period [2]. It is a unique constitutional arrangement where the presiding officer and their deputy address their resignations to each other rather than to the President of India [1].

Sources

1. [1] Indian Polity, M. Laxmikanth(7th ed.) > Chapter 55: Constitutional Prescriptions > Table 55.7 Constitutional Prescriptions with Respect to Resignations > p. 461
2. [2] Indian Polity, M. Laxmikanth(7th ed.) > Chapter 23: Parliament > Speaker of Lok Sabha > p. 229