If you want a fully featured terminal interface, curses is the way to go: https://docs.python.org/3/library/curses.html
For this, though, readline is pretty good: https://docs.python.org/3/library/readline.html
It should be noted that, despite being in the standard library, it might not be available on some windows python installs. (python's readline module not available for windows?)
import readline
def setup(text):
readline.insert_text(text)
readline.redisplay()
readline.set_pre_input_hook(lambda: setup("DEFAULT"))
a = input("Type your input here: ")
print(f"\n\"{a}\"\n")
readline.set_pre_input_hook(lambda: setup("OTHER DEFAULT"))
a = input("Type your input here: ")
print(f"\n\"{a}\"")