Switch off 2 step verification

Do you have 2 step or two factor authentication?

2 step verification can be turned off via this steps

1. sign in to your  Apple ID account page.     
2. Go to security, click edit
3. Click turn off two step verification

Two factor authentication cannot be turned off after 14 days after your enrollment in two factor authentication has ended

If you cannot access your Apple ID anymore due to this, you can enroll in account recovery https://support.apple.com/en-us/HT204921

You cannot turn off 2 factor authentication. You need to add another trusted number. See this for help. Two-factor authentication for Apple ID - Apple Support