make key and it to remote server for backups

mkdir -pv ~/.ssh;ssh-keygen -t rsa -b 2048 -C "$(whoami)@$(hostname)-$(date -I)" -f ~/.ssh/"$(whoami)"
chmod 600 ~/.ssh/"$(whoami)".pub
ssh-copy-id -i ~/.ssh/"$(whoami)".pub user_name@server_ip
ssh -i ~/.ssh/"$(whoami)" user_name@server_ip

or manually add it to host under user:

mkdir -pv /home/key_name/.ssh/ && nano /home/key_name/.ssh/authorized_keys && chown -Rv key_name:key_name /home/key_name/.ssh