How to give permission to a specific Account

i m creating a Account ,now i want to give this account mutation permission to a specific account using Account
how to do this…
please share a example.

The example in the documentation shows how to do exactly this

Create a permission which contains an AccountPolicy. In the docs is anonymous - change this to whatever the account ID is that you want to give permission to.
This line accounts: [{ hypi: { id: "anonymous" } }]