Without more information on what actions you've already taken, it's difficult to tell what your situation is.
Credit Karma and TurboTax are separate products, and each requires a separate account. You can’t use your TurboTax login information to sign in to Credit Karma and vice versa.
If you have existing accounts with both TurboTax and Credit Karma, see the Credit Karma Help article Linking your TurboTax account to Credit Karma for guidance in linking your accounts. If you don't yet have a Credit Karma account and need to create one, see their Create your account page.
You might also research this issue by using Credit Karma's Help Center.
If these resources aren't helpful, feel to re-post with more details.