Dear Abdul,

Professor Mullahy on statalist answers this question better than I can. I agree with him that you would need to perform a tangential analysis to get an IMR if you intend to go with Heckprobit instead of Heckman. There are also ways to achieve a strong bound on the IMR or even approximate if necessary, as shown in the link below. I hope this helps!

https://www.statalist.org/forums/forum/general-stata-discussion/general/1419647-how-can-i-get-the-mills-ratios-for-my-heckprobit-model

Article On approximating Mills ratio

Dear Nathan Zavanelli , thanks for the link. It answered my question.