Version 1.0, 20 August 2021

Version history:

1.0, 20 August 2021

What are ‘hexadecimal’ codes?

...

This keyboard layout is pre-installed, but it is not active by default and therefore you won’t see it, so you have to ‘activate’ it (only once).

Activate Unicode Hex Input in macOS

...

Go to System Preferences… and click Keyboard to select your keyboard options

...

In your menu bar, near the right, you now see that you have two active keyboard layouts: one is your primary keyboard layout (in this case ‘ABC’, a Latin-script keyboard associated with the English language), and the other is Unicode Hex Input, which you can now select and use. Note also that you now have access to two new items: ‘Show Emoji & Symbols’, a bit of a misnomer since it in fact gives you access to all of Unicode; and ‘Show Keyboard Viewer’, which is self-explanatory.

Use Unicode Hex Input in macOS

...

1) Select Unicode Hex Input in the keyboard menu in the menu bar. It can be used in any application that accepts text.

...

The macOS palette commonly known as ‘Show Emoji & Symbols’, also known as the Character Viewer, gives users access to Unicode hex codes longer than 4 digits, the limit of Unicode Hex Input.

	Choosing ‘Show Emoji & Symbols’ in the keyboard menu brings up the Character Viewer palette, which gives you access to all of Unicode on macOS.
	When first opened, the palette shows a limited list of character categories, and it defaults to ‘Smileys & People’ emoji. Serious users of text will want to customise the list of character categories by clicking on the ⚙ (‘gear’) dropdown menu. Note that you could also just key any Unicode hex scalar value in the ‘Search’ box, hit Return, and directly go to the character that is sought.
	Scroll in the list of character categories to slect select the ones that you want to appear by default, and deselect unwanted others.
	At the bottom of the list come the Code Tables. Clicking on the triangle will reveal several encodings, the first and most important of which is ‘Unicode’. Checkmark that.
	In the left-hand column you can now directly select ‘Unicode’, and in the middle column the top pane lets you scroll down all Unicode ranges. The middle bottom pane shows the contents of the Unicode range selected in the top middle pane. In this case, it is the first Unicode range that has five-digit hexadecimal scalar values, which you could not access by using the Unicode Hex Input. Double-clicking any character will insert that character at the insertion point in any text application that is active (= whose window is topmost next to the Character Viewer palette). You can drag column/pane boundaries to enlarge any panes that need it, for instance the middle bottom pane with all the characters.
	You could scroll down all the way to 0002B820 to get to the Unicode range ‘CJK Unified Ideographs Ext. E’, and then scroll down in the bottom middle pane to search for a character you might need, e.g. U+2CC5F. But you could also just key ‘2cc5f’ in the ‘Search’ box to quickly access the character you need. BTW, the ‘Search’ box also accepts (parts of) Unicode character names, so that is also a very useful method of finding a character, maybe when you know its name but not its code.