Open up your user’s .bashrc file in whichever text editor you like, I usually use gedit for quick things like this.
Now add the following lines to the bottom of the file, replace the somefolder path with the path to the folder that you want to add to PATH. Then save the file, and close the text editor.
PATH=$PATH:/home/user/somefolder export PATH
To make the changes take, run the following in the terminal.
Done! You can now access anything in that folder from the bash prompt without typing the path.