I thought this was done using the More Options button but when I click the button I don't get any options.

Either I am having a bad day or something is broken.

 

Hello,

[spoiler]this is the spoilertext[/spoiler]
should give this as result:

Spoiler

this is the spoilertext

There are more bb-codes that can be used.
Here is the list of bb-codes available:
https://forum.allaboutcircuits.com/help/bb-codes

Bertus

 

I thought this was done using the More Options button but when I click the button I don't get any options.

Either I am having a bad day or something is broken.

Nope, it is all manual code. You can also put a single slash through text with an s in brackets. like this