Submitting your information for pre-approval is the first part of the application—during this step, only a soft pull is performed, which won't affect your credit score.
If you're pre-approved, you'll be invited to submit your full application for one of the Petal cards you qualify for. Once you apply, a hard inquiry is completed, which may affect your credit score.
If you’re not eligible for a Petal card at this time, Thrive or Cash Advance may be a better fit.