If the font came pre-installed on your Mac or with Windows, you generally have the right to use it for personal and professional projects on that device.
You can find more information about its distribution and technical specifications on Microsoft's Typography page . Third-Party Platforms: stkaiti-sc-bold font free download
(CJK Unicode font)
STKaiti-SC-Bold cannot be legally downloaded for free from third-party websites because it is a commercial, copyrighted typeface owned by Changzhou SinoType. However, you likely already have free, legal access to it through your operating system or software suite. Google Groups If the font came pre-installed on your Mac
If you need a similar "Kaiti" (regular script) style for free commercial use, consider these open-source options: Google Fonts - Ma Shan Zheng : A creative, calligraphic Chinese font available for free download on Google Fonts AR PL KaitiM GB However, you likely already have free, legal access