! LaTeX Error: File `IEEEtran.cls' not found

If you are an Ubuntu, Debian or Linux Mint user try this:

sudo apt-get install texlive-publishers

You can simply download the folder in this link https://ctan.org/tex-archive/macros/latex/contrib/IEEEtran?lang=en;

Then, you have to copy the file IEEEtran to the folder where your working file are in. Have a nice day.