How to enter different whitespaces in Pages?
Unicode Hex Input

You can use Unicode Hex Input to enter the characters that you want. Go to System Preferences → Keyboard → Input Sources and enable Unicode Hex Input. Then you can enter the characters by holding ⌥ and typing the Unicode code.

Multi-stroke Key Bindings

You can edit ~/Library/KeyBindings/DefaultKeyBinding.dict and create a multi-stroke key binding for each of the characters that you want to enter. More information is available on this blog post:


http://blog.macromates.com/2006/multi-stroke-key-bindings/


Press and Hold


Navigate to System/Library/Input Methods/PressAndHold.app/Contents/Resources/.
Backup the Keyboard-en.plist file.
Append the following to the Keyboard-en.plist file (before the closing &lt;/dict&gt;&lt;/plist&gt;).

&lt;key&gt;Roman-Accent-t&lt;/key&gt;
&lt;dict&gt;
    &lt;key&gt;Direction&lt;/key&gt;
    &lt;string&gt;right&lt;/string&gt;
    &lt;key&gt;Keycaps&lt;/key&gt;
    &lt;string&gt;t                   ​     　 &lt;/string&gt;
    &lt;key&gt;Strings&lt;/key&gt;
    &lt;string&gt;t                   ​     　 &lt;/string&gt;
&lt;/dict&gt;


There are a number of different spaces included in the strings above.


Feel free to change the Roman-Accent-t to any character you wish, providing it does not already have Press &amp; Hold keys assigned.

Text Shortcuts

Go to System Preferences → Keyboard → Text and enter some shortcuts.