Abu Malik Ashaja'i reported on the authority of his father that whenever a person embraced Islam, Allah's Messenger (ﷺ) instructed him to recite
اللَّهُمَّ اغْفِرْ لِي وَارْحَمْنِي وَاهْدِنِي وَارْزُقْنِي
" O Allah, grant me pardon, have mercy upon me, direct me to the path of righteousness and provide me sustenance."
[Ref: Saheeh Muslim , 2697a]
The callers to Islam should revive this sunnah and ensure that the revert recites this atleast in english