user_data = input()
with open('file.txt', 'w') as file:
file.write(user_data)
user_data_list = []
with open('file.txt', 'r') as file:
for line in file:
user_data_list.append(line)
user_data = user_data_list[x]
Но, думаю настоящие программисты делают по другому