Difference between the usage of “a” and “any” [duplicate]

Question

This question already has an answer here:

• Difference between “a” and “any” 2 answers
• “Is there a” vs “is there any”? 4 answers

In the following writing of mine, can you please tell me "a" or "any", which one would you prefer? I know both can be used in the given context but want to which one is better. Can anyone having good knowledge in the language please answer this?

1- According to grammarians, "it is I" is grammatical. "It is me" is ungrammatical because Any/A pronoun that follows a linking verb should be in its subject case.

Answer 1

Referring to: "Is there a" vs "is there any"? the difference is explained in terms of a=particular any=general. Now "a pronoun" also implies a singular pronoun following, whereas "any pronoun" can potentially cover multiple pronouns. In this case I'd prefer "any" as the rule also applies to multiple pronound: "It is he and I" (assuming a he provided by context).