If your visa application was refused with a “214 (b)” notation, it is a final refusal for this application. Section 214(b)* denials are not permanent. If you have new information or if your overall circumstances have changed significantly, you may reapply. Applicants who provide identical information in a second interview rarely get a different result.
If your visa application was refused with a “221 (g)” notation for further administrative processing, please read the instructions on the handout you were given at the conclusion of your interview.