Sometimes I develop on a Macintosh computer. I might be using Adobe tools and when I use those tools I might select fonts which are available on the Macintosh computer. Then when I transfer that thing that I’m working on to a PC I can discover that the fonts I want are not available on the PC.
Although you can look for similar fonts to replace the ones that you used on the Macintosh, I’m going to share with you how you can download those Apple system fonts, unpack them and install them on your computer.