Accountability partner is another person with similar goals as you. And you both have mutually agreed to support each other to achieve your desired goals.
With an accountability partner, you both each agree to meet regularly. Share progress updates, provide feedback, brainstorm how to overcome your challenges.
Ideally, it would be someone who is tackling the same goal as you.But often it is hard to find others working on a similar goal and starting at the same place as you.
While you want someone nonjudgmental; you also do not want someone who accepts all your excuses. They should be able to call you out when you have done what you are supposed to do.