How does the MD editor of CSDN input superscripts and subscripts? The input method of formula and non formula is different

There are two ways to print subscripts

As the title ： Now I want to print one X1（1 It's a subscript ）：

The formula

$X_1$

effect ：$X_1$
Special , If the subscript exceeds one character , Need to add {}：

$X_{
    ij}$

effect ：$X_{ij}$

Non formula

X~1~

X₁
In this case, there is no need to worry about multiple characters ：

X~ij~

effect ：X_ij

How to print superscript ？

The reason is consistent with the subscript , Both formula and non formula use ^ that will do