Serif font such as
Times New Roman is usually used in printing document in Windows.
What is the equivalent font in Apple?
Helvetica Regular is the default typeface for most of Apple’s apps that can print, including Pages, TextEdit and Numbers.
Apple typically uses a mixture of Helvetica and Lucida Grande for their UI. A lot of Apple’s marketing material is set in Myriad Pro. iOS is mostly Helvetica.
As @Const says in the comment above, Times New Roman is available on all Macs from 10.5 on.
However, the "old-school" Mac equivalent to Times New Roman is Times...somewhat fitting, because as this article discusses, Times Roman and Times New Roman were Depression-era rivals:
After Monotype completed Times New Roman, it had to license the design to then-rival Linotype, because the Times used Linotype’s typesetting machines. (Think of Monotype and Linotype as the Depression-era Microsoft and Apple.) Since then, Monotype has sold the font as “Times New Roman” and Linotype has marketed its version as “Times Roman.”