One click, and the form is filled in correctly.

# Generated by Verifill — Try-it page · Verifill
# Each selector was REPLAYED on the page: it matches the field and only that field.

# Title  —  Choice (radio) · required · by name + value · options: Ms | Mr
Click Element    css=input[name="title"][value="Ms"]

# First name  —  First name · required · by id
Input Text    css=#prenom    Salma

# Date of birth  —  Date of birth (adult) · required · by id
Input Text    css=#naissance    01/01/1990

# Nationality  —  Country / Nationality · required · by id · options: British | American | Irish | Canadian | Moroccan | Other
Select From List By Label    css=#nationalite    British

# Username  —  required · by name
Input Text    css=input[name="username"]    VALUE_TO_ENTER

# How did you hear about us?  —  List (auto choice) · by id · options: A friend | A search engine | Social media | An article | Other
Click Element    css=#source    # opens the list
Click Element    xpath=//*[@role="option"][normalize-space()="A friend"]    # picks “A friend”

# --- inside the “Delivery address” frame ---
# --- in the frame 0 (4 element(s)) ---
Select Frame    css=iframe#cadre-livraison    # frame located by id
# Recipient's name  —  required · by id
Input Text    css=#dest    VALUE_TO_ENTER
Unselect Frame

# Generated by Verifill — Try-it page · Verifill
# Each selector was REPLAYED on the page: it matches the field and only that field.

# Title  —  Choice (radio) · required · by name + value · options: Ms | Mr
driver.find_element(By.CSS_SELECTOR, "input[name=\"title\"][value=\"Ms\"]").click()

# First name  —  First name · required · by id
driver.find_element(By.CSS_SELECTOR, "#prenom").send_keys("Salma")

# Date of birth  —  Date of birth (adult) · required · by id
driver.find_element(By.CSS_SELECTOR, "#naissance").send_keys("01/01/1990")

# Nationality  —  Country / Nationality · required · by id · options: British | American | Irish | Canadian | Moroccan | Other
Select(driver.find_element(By.CSS_SELECTOR, "#nationalite")).select_by_visible_text("British")

# Username  —  required · by name
driver.find_element(By.CSS_SELECTOR, "input[name=\"username\"]").send_keys("VALUE_TO_ENTER")

# How did you hear about us?  —  List (auto choice) · by id · options: A friend | A search engine | Social media | An article | Other
driver.find_element(By.CSS_SELECTOR, "#source").send_keys("A friend")

# --- inside the “Delivery address” frame ---
# --- in the frame 0 (4 element(s)) ---
driver.switch_to.frame(driver.find_element(By.CSS_SELECTOR, "iframe#cadre-livraison"))  # frame located by id
# Recipient's name  —  required · by id
driver.find_element(By.CSS_SELECTOR, "#dest").send_keys("VALUE_TO_ENTER")
driver.switch_to.default_content()

// Generated by Verifill — Try-it page · Verifill
// Each selector was REPLAYED on the page: it matches the field and only that field.

// Title  —  Choice (radio) · required · by name + value · options: Ms | Mr
document.querySelector("input[name=\"title\"][value=\"Ms\"]").click()

// First name  —  First name · required · by id
document.querySelector("#prenom").value = "Salma"

// Date of birth  —  Date of birth (adult) · required · by id
document.querySelector("#naissance").value = "01/01/1990"

// Nationality  —  Country / Nationality · required · by id · options: British | American | Irish | Canadian | Moroccan | Other
document.querySelector("#nationalite").value = "GB"

// Username  —  required · by name
document.querySelector("input[name=\"username\"]").value = "VALUE_TO_ENTER"

// How did you hear about us?  —  List (auto choice) · by id · options: A friend | A search engine | Social media | An article | Other
document.querySelector("#source").value = "A friend"