$PATH is a default Linux variable that contains directories to commands. echo or printf can be used to display the current directories in the $PATH variable.
Which should return something like this.
Directories can temporarily be appended to the PATH variable like this.
Better yet, PATH can be defined in your /home/username/.bash_profile file, so that every time you sign into the system, your PATH will contain the directories defined in your .bash_profile file.
PATH=$PATH:/home/john.doe/.local/bin:/home/john.doe/bin export PATH
You would then want to log out of the system, log back in, and echo or printf should now contain the additional directories.