Is the call to God obligatory upon every Muslim man and woman, or is it limited to scholars and students of knowledge only?

It is permissible for every Muslim who has insight into what they are calling to, whether they are a scholar, a student of knowledge, or a layperson, to engage in da'wah (calling to Allah), because the Prophet, peace and blessings be upon him, said: "Convey from me, even if it is a single verse." A prerequisite for the caller (da'i) is knowledge of what they are calling to. It is not permissible for them to call to Allah out of ignorance or emotion, as that could lead to prohibiting what Allah has made lawful or obligating what He has not obligated, which is a serious matter that results in fabricating lies against Allah.