This question is rather confused. What does the Alt key have to do with your requiring two backticks ` [not tildes, btw, they're ~ ]
Stack Exchange uses markdown for formatting, which means two backticks surround a code block like this. This is entered as
`a code block like this`
If you want to enter any markdown & not show as such, then you can ...
How can I type two backtick characters without formatting my text in unwanted way?
Use \ as an escape character:
This is some text with `backticks` and some more `text with backticks`
This is some text with \`backticks\` and some more \`text with backticks\`
Markdown allows you to use backslash escapes to generate ...