add ssh key to authorized_keys in all servers (give access to all server for a new key)

copy.sh

#!/bin/bash

# create a file named key which contains the public key for new user

export SERVERS="ip1 ip2 ip3"

for server in $SERVERS
do
    echo "============="
    echo $server
    ssh $server "hostname"
    cat key | ssh ${server} "tee -a ~/.ssh/authorized_keys"
done

Use as ssh-copy-id -i /paht/to/key/file ${server}

@vahit I already have access to server with my ssh key, This scripts simply connects to those servers and gives access to second person