Pip got 0 points on everything how to appeal

A letter from a GP is never the best evidence to send because a GP will not spend enough of time with you to know how you manage the descriptors. If they know it's because you've told them and then it becomes hearsay.

You have 1 month to request the Mandatory Reconsideration. (MR) You should put this in writing stating where and why you think you should have scored those points. Please do not ring to request it.

There's a form online you can use and print off or you can just write a letter.

https://assets.publishing.service.gov.uk/media/656088523d7741000d420162/if-you-disagree-with-a-decision-made-by-dwp.pdf

It can take up to 15 weeks for a decision on the MR once they receive it.

Appeal refers to Tribunal. Are you saying you took It that far and lost?

I replied to you on another thread with this comment.

It's not unusual for the MR decision not to change because the majority of them don't. The stats suggest only about 24% of MR decisions change at that stage. More often that not the MR decision is a copy and paste of the original decision. 

There's much more chance of success at Tribunal stage providing you either appear in person or have a telephone/video hearing and then there's about 66% chance of success. 

It's also your responsibility to provide the evidence to support your claim and not their responsibility to request medical records.