FIGlet is a program that creates large characters out of ordinary
screen characters

 _ _ _          _   _     _
| (_) | _____  | |_| |__ (_)___
| | | |/ / _ \ | __| '_ \| / __|
| | |   <  __/ | |_| | | | \__ \_
|_|_|_|\_\___|  \__|_| |_|_|___(_)

These days you can use online websites like this to generate the art for you but if you want to install the program on your computer and run it from a terminal you can do so by following below steps:

1. Clone the git repo
2. add #include<getopt.h> to figlet.c
3. run sudo make install

This will install figlet under /usr/local/bin directory and fonts will be under /usr/local/share/figlet. You can download more from http://www.jave.de/figlet/figletfonts40.zip. Unzip the file and copy the contents to /usr/local/share/figlet.

copy -n *.* /usr/local/share/figlet/.

The -n option prevents overwriting existing files. Once installed you run like this:

/usr/local/bin/figlet -f big

Here big is the font name. Run /usr/local/bin/showfigfonts to see what all the fonts look like.
/usr/local/bin/figlist will list all the installed fonts.

Further Reading: https://www.linkedin.com/pulse/creating-ascii-text-banners-linux-terminal-ali-imran-nagori-ojjbf