Do you want to approve your iPhone from a Mac?
There are 3 ways of solving this problem: Through Your iPhone, Through Your Mac and Using Two Factor Authentication.
The solutions are briefly described below, also have a look at iPhone meme
a.) Through Your iPhone (iOS 12.1.3)
- Go to settings on your iPhone.
- Open Passwords & Accounts.
- Click on icloud.
- Open Keychain and Toggle ON iCloud keychain.
- Enter the password for your iCloud account.
- Enter Your iPhone Passcode.
- Enter Your Mac Password.
It’s done, you have approved your iPhone without accessing your mac.
b.)Through Your Mac:
- Turn off iCloud Keychain on all apple device using the same iCloud ID.
- On your iPhone, go to Setting >Keychain and tap Approve with Security Code.
- When prompted for the 4-digit iCloud Security code tap Forgot Code.
- Follow the prompts to reset the code.
- Now, this device is iCloud Keychain enabled and working.
- Now on your MacBook, enable iCloud Keychain.
- Enter your iCloud password in the prompt on your iPhone.
- iCloud Keychain is now enabled.
c.) Through 2- Factor Authentication: if you have turned on 2- Factor authentication you can enable iCloud keychain without approval from another device.
- Click on the Apple menu on your MacBook.
- Open System Preferences,
- select iCloud.
- Click Account details, under your account logo.
- Select the security tab.
- Turn On Two Factor Authentication.