Bracket notation is writing different brackets, surrounding single unit, including for bra vectors and for ket vectors. Unfortunately, I see no such template in OneNote math
How to create an equation in Microsoft OneNote using Equation Tools
Script Editor - Jitterbit's Success Central
How to insert underbrace in a word document - Super User
Creating sub-numbered lists in OneNote - Super User
Create equations in OneNote using Equation Tools - Microsoft Support
How to bracket over multiple lines of text in Word document?
Turn Math Assistant on or off in OneNote Class Notebook - Microsoft Support
Is there a keyboard shortcut in Word for typing an arrow symbol? - Super User
How to type a greater than or equal to sign in Microsoft Word - Quora
What are the keyboard shortcuts for adding emojis in Microsoft Word? - Quora
Write Math PROPERLY on OneNote with Ink
How to type a square root symbol on an iPhone or iPad - Quora
How to insert Equations and Symbols into a page in OneNote, Adding Math Equations in Pages
Add mathematical equations in Pages on iPad - Apple Support