Answered by Shaykh Faraz Rabbani
If I omit to perform the Iqama does it nullify my prayer?
Answer: walaikum assalam wa rahmatullah,
I pray this finds you in the best of health and spirits.
The call to commence (iqama) is a confirmed sunna for men–as the basis of their prayer is the group pray, so their individual prayer resembles the group prayer. Omitting the call to commence doesn’t invalidate the prayer, as omission of sunna actions diminishes reward but doesn’t affect validity.
[ref: Shurunbulali, Maraqi al-Falah; Ibn Abidin, Radd al-Muhtar]