After I enter my mileage used as a job expense as a delivery driver it does not increase my refund amount. Why? It shows over $3000

[MarilynG]

After you enter all your job-related expenses that go on Form 2106, that amount is carried to Schedule A, Itemized Deductions.

If your Itemized Deductions are less than the Standard Deduction, your refund amount won't change.   If you are still entering expenses, that could still change though.

Here's some info that may help you:

https://ttlc.intuit.com/replies/3302313