I have found that the "Send_Keys" is not working for the following website due to the error "AttributeError: 'list' object has no attribute 'send_keys'".. Kindly note that I am using 'pycharm' editor
https://login.salesforce.com/?locale=eu
driver.find_elements_by_css_selector("input[id='username']").send_keys("testusername")
But the same command is working perfectly when using for the following
https://rahulshettyacademy.com/angularpractice/
driver.find_element_by_css_selector("input[name='name']").send_keys("testname")
find_elements_by_css_selector, which returns a list of found elements. The second one callsfind_element_by_css_selector, which returns a single element.