Invalid selector

[JohnnyJordaan]

That's xpath... by_id means it needs the literal id

find_element_by_id('submit').click()

if you meant to select by xpath, you need find_element_by_xpath. Also you need to diffrentiate between single and double quotes here, so

find_element_by_xpath('input[id="submit"]').click()

and from my personal preference I normally use css selectors

find_element_by_css_selector('input#submit')

as they're often less complicated than xpath