LaTeX sets aside a few characters for special purposes; they are called reserved characters or special characters. Here they are:
# $ % & { } _ ~ ^ \
The meaning of all the special characters is given elsewhere in this manual (see Reserved characters).
If you want a reserved character to be printed as itself, in the text
body font, for all but the final three characters in that list simply
put a \ in front of the character. Thus, typing \$1.23
will produce $1.23 in your output.
As to the last three characters, to get a tilde in the text body font
use \~{} (omitting the curly braces would result in the next
character receiving a tilde accent). Similarly, to get a text body
font circumflex use \^{}. To get a backslash in the font of
the text body, enter \textbackslash{}.
To produce the reserved characters in a typewriter font, use
\verb!! as below (the \newline in the example is there
only to split the lines in the output).
\begin{center}
\# \$ \% \& \{ \} \_ \~{} \^{} \textbackslash \newline
\verb!# $ % & { } _ ~ ^ \!
\end{center}