from selenium import webdriver
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.common.by import By
import time
browser = webdriver.Chrome(executable_path='E:/chromedriver.exe')
log_post = ''
pass_post = ''
browser.get('https://mail.rambler.ru/')
time.sleep(5)
mail_find_guard = browser.find_element (By.XPATH, '/html/body/div[1]/div/div/div[1]/article/form/section[1]/div/div/div/input')
mail_find_guard.send_keys(log_post)
mail = browser.find_element (By.XPATH, '/html/body/div[1]/div/div/div[1]/article/form/section[2]/div/div/div/input')
mail.send_keys(pass_post)
mail.send_keys(Keys.ENTER)
time.sleep(2)
По идеи должно сработать.