Where the author rules diverge
Most free generators format a single author correctly and then guess. APA 7 names up to twenty authors in the reference, with an ampersand before the last; at twenty-one or more you give the first nineteen, an ellipsis, then the final author. MLA 9 stops far earlier — three or more authors becomes one name and et al.
Chicago author-date lists every author up to ten in the bibliography, then shortens to the first seven plus et al. IEEE inverts the pattern entirely, printing initials before the surname — J. K. Sharma rather than Sharma, J. K. — and ordering entries by first appearance in the text instead of alphabetically.
Harvard is a family of styles rather than one, so departments disagree on where et al. begins. The common British convention, followed here, names up to three authors and shortens at four. If your handbook sets a different threshold, that is one line to adjust rather than a bibliography to rebuild.
The in-text citation is half the job
A reference list that is perfect on its own still loses marks when the citation in the sentence does not match it. APA 7 writes (Sharma & Iyer, 2021) inside brackets but Sharma and Iyer (2021) in running text, and drops to (Sharma et al., 2021) from three authors onwards, including the very first mention.
MLA 9 drops the year and the comma: (Sharma and Iyer 45). Chicago author-date keeps the year and separates the page with a comma: (Sharma and Iyer 2021, 45). Harvard normally punctuates as (Sharma and Iyer, 2021, p. 45). IEEE prints a bracketed number, [3], and carries no name at all.
Because both forms come from the same fields, they cannot drift apart. That matters most when the style changes late. A supervisor asking for Harvard instead of APA changes the reference list and every bracket in the body, and the usual outcome is that only the reference list gets rewritten.
Missing dates, organisations and names as typed
Undated web pages are the common case. APA, Harvard and Chicago author-date all put n.d. where the year would go, and it carries through to the bracket as (Ministry of Education, n.d.). Leaving the year empty produces that rather than a blank, and the date you opened the page is not a substitute for it.
Organisations are authors as well, and they are never inverted. The Ministry of Education stays the Ministry of Education; Education, Ministry of is the classic generator failure. A corporate author is kept whole instead of being split at the last space and turned into a surname with an initial in front of it.
Names can be entered either way round. Sharma, Priya and Priya Sharma produce identical output, because the comma is read as family-name-first rather than as a second author. That covers Indian names typed surname-first out of form-filling habit, and single-word names, which stay intact instead of being reduced to an initial.