If you want to appeal a VA decision on a disability claim, you have three options: file for a higher-level review, file a supplemental appeal, or appeal directly to the Board of Veterans’ Appeals (BVA).
If you don’t have any additional evidence to present, you can request a higher-level review, in which you are asking for someone higher up at the VA regional office to look into your case. Just know, that you cannot file for higher-level review twice in a row.
If you have new evidence to submit, you can choose option two, the supplemental claim lane which will also be reviewed at your regional VA office.
The third lane is called the notice of disagreement lane which involves appealing to the BVA where a judge decides on your case. Within this lane, there are three sub-routes: the direct review docket (if you have no new evidence),the new evidence docket (if you have new and relevant evidence), and the hearing docket (which allows you to present your case in person to a BVA judge).