Selenium launch browser in specific path (for example ./firefox/firefox.exe) (Python3)

Selenium searches the webdriver through the directories on sys.path, so you would first have to do something like that:

import sys
from selenium import webdriver
sys.path.insert(0,'/path/to/firefox')
driver = webdriver.Firefox()
driver.get('https://www.google.com')

Have you tried webdriver-manager library? It's amazing, you just need to install it:

pip install webdriver-manager

and launch your code like this:

from selenium import webdriver
from webdriver_manager.firefox import GeckoDriverManager
driver = webdriver.Firefox(executable_path=GeckoDriverManager().install())

that package downloads you needed geckodriver automatically. Don't forget path 'executable_path' while launching driver. As well you can you chromedriver, like that:

from selenium import webdriver
from webdriver_manager.chrome import ChromeDriverManager
driver = webdriver.Chrome(ChromeDriverManager().install())