If you are talking about it as a field of study you would capitalize it, but if you say I study math in general then not capitalized
Yes you do capitalize Math because the word Math is a Proper noun
No.
do you capitalize the word protestant
No it shouldn't be capitalized.
It is not necessary to capitalize the word "yo".
No, you do not capitalize the word drama.
No it shouldn't be capitalized.
Yes, you must capitalize the first word, UNLESS it is a small word, such as "It" or "A" or "The".
Unless "it's" is the first word, there is no need to capitalize.
No, you do not capitalize the second word in the complimentary closing.
Yes, you should capitalize the word after a comma in a sentence.
In a title, you generally do not capitalize the word "for" unless it is the first word or part of a proper noun.