Unicode is a massive, sprawling effort that pairs a number to every unique character in a language, every punctuation mark, every math symbol, and much more. And nearly all of it is available within macOS but not always easy to find.
If you are trying to type unique characters such as the Euro sign or a pound sign see this separate story: How to type Æ, €, #, @, © and more special characters on a Mac.
There’s a semi-hidden way to access special symbol sets in Unicode, and a somewhat obscure method of searching for specific symbols across all of macOS’s included Unicode characters.
Read more at Macworld.com