Hello _ash_0,
Let's start off by checking the helpful steps in this article which can help with this issue: Get a verification code and sign in with two-factor authentication - Apple Support. If you have the device in question, but not the number, you can still try the steps in this section of the article:
"Get a code from Settings on your trusted device: If you can’t receive a verification code on your trusted devices automatically, you can get one from Settings, even if your device is offline.
From your iPhone, iPad, or iPod touch
If your device is online:
- Go to Settings > [your name].
- Tap Password & Security > Get Verification Code.
If your device is offline:
- Go to Settings > [your name].
- Tap Password & Security.
- A message says "Account Details Unavailable." Tap Get Verification Code.
From your Mac
- Go to Apple menu > System Preferences, then click Apple ID.
- Click Password & Security > Get Verification Code."
Let us know if we can help with anything else at all or if this doesn't settle your issue so we can look into this further with you. Thanks and have a fabulous day!