how to disable 2 step verification

According to Apple:

Make sure that you're still signed in to iCloud on each of your devices. You might be asked for your Apple ID password.

1. Sign in to appleid.apple.com.
2. In the Sign-In and Security section, click Account Security.
3. Click Turn Off two-step verification. Click again to confirm.
4. Create new security questions and verify your date of birth.

You'll get an email confirming that two-step verification for your Apple ID is off.

Is this what you are asking about?

Two-factor authentication for Apple ID - Apple Support

You might be asking about Apple 2 Factor Authentication.

Once you have started it, you cannot stop.