As pointed out in this question, in TeXShop there is no way to make source paragraphs (i.e. long lines with no hard wraps) follow source indents automatically, that is, while typing. The solution ...
How do I make long paragraphs follow the source indents in TeXShop? This what I usually get: How do I make succeeding lines follow the indent of the first line? This is so that it would be easier to ...