How does a credit card company verify someone’s income?
When applying for a credit card one can now be “instantly” approved (or declined). I understand how creditors can access and review one’s credit report in a matter of seconds, but how can a creditor “instantly” verify the income that you have reported?
For that matter, how do they verify or check your income at all? (even when it’s not an “instant” application)

If the credit card company is a good company, they call the references that are listed on the application. As a secretary, I often get calls verifying employment.
While the companies can verify your employment, they cannot practically verify your income.
This is because employers are required by law to protect your privacy, so they cannot give your salary information unless you explictly authorize it — which is not practical.
There are “good” credit card companies?????
Your employment history is listed in your credit report. Any time you file an application for a loan, everything you entered gets sent to the bureaus. But not your income amount.
If they are giving you “instant” approval, it’s because of your credit score.