Intro
He was the older brother of the famous Dr. Allama Iqbal. His father was Sheikh Nur Ahmad. He seems to have converted to Ahmadiyya in the late 1890’s. Ata Muhammad seems to have been mentioned in the list of the first 313 Ahmadi’s (see Dard, Ahmadi #224, written as Munshi Ata Muhammad from Sialkot). It is reported that Ata Muhammad renounced Ahmadiyya some years before his death and none of his other children accepted it. He died on Dec 22, 1940. He is buried in Kashmirian graveyard, Sialkot. He had an uncle who also joined Ahmadiyya, his name was Ghulam Qadir, a Munshi from Siaklot. 

Links and Related Essays
https://ahmadiyyafactcheckblog.com/2019/12/04/who-is-sheikh-noor-muhammad-died-1930/

https://www.dawn.com/news/1065249

https://en.wikipedia.org/wiki/Muhammad_Iqbal

Schimmel, Annemarie (1962). Gabriel’s wing: a study into the religious ideas of Sir Muhammad Iqbal. Brill Archive. pp. 34–45.

Mir, Mustansir (2006). Iqbal. I.B. Tauris. ISBN 1-84511-094-3.