hey, I got success If someone else is looking for this.
So here are the steps.
you need to have write_order_edits rights via scope when getting auth access token.
then you need to pass global order id of graphql mutation
first call mutation orderEditBegi
it will return calculated order id
then pass that calcualted order id into
mutation orderEditAddCustomIte
then at the end do call orderEditCommit with the same calcuated order id
and thats it, thanks.