Is there any way I can define a variable in LaTeX?

Question

In LaTeX, how can I define a string variable whose content is used instead of the variable in the compiled PDF?

Let\'s say I\'m writing a tech doc on a software and

Answer 1

This works for me: \newcommand{\variablename}{the text}

For eg: \newcommand\m{100}

So when you type " \m\ is my mark " in the source code,

the pdf output displays as :

100 is my mark