Well i use Google Authenticator . how i can save the 2af key if it keep change always
I have Google Authenticator on my phone and I found no way to transfer/backup the info out of it. But my phone is also not rooted.
The only way I found to "backup" such info is at the original website offering 2FA: when you activate the 2FA and get the key, you usually can see the private/seed for your 2FA codes. That's the one you should save.
Some sites offer only a seed to disable the 2FA, that is also fine for emergencies.
PS. This thread should be renamed 2FA instead of 2AF and maybe moved into technical area.