Save the private key the first time Apple offers it.
On the Team Keys page, use Download API Key in the row for the AllMyApps key. The Key ID and the .p8 file must belong to the same key.
- Download the .p8 as soon as Apple shows the link. The link disappears after you use it, and Apple does not keep another copy.
- Keep the file private until you import it into AllMyApps. Do not put it in a code repository, and do not send it by email or chat.
- If the download link is already gone, create a new Team Key named AllMyApps, download its .p8 immediately, and use that new Key ID.