Switch to iframe by using switch_to.frame() method and index value.
Example:
Prompt_Alert_Popup.py
from selenium.webdriver.common.by import By
from selenium import webdriver
import time
driver = webdriver.Chrome("/Users/admin/Documents/Others/Drivers/chromedriver.exe") # Using Chrome Driver
driver.get("http://www.dummypoint.com/Frame.html")
assert "Selenium Template" in driver.title
ele = driver.find_elements(By.TAG_NAME, "iframe")
# To display number of Iframes in web page
print("List of iframe : ", len(ele))
# Switch to iframe by its index value
time.sleep(2)
driver.switch_to.frame(1)
# After switching get the text from iframe using ID locator
data = driver.find_element(By.ID,"framename")
print("Frame Name is : ",data.text)
time.sleep(2)
driver.quit()