You can use the following command to copy your SSH public key to a Linux server.
ssh-copy-id -i ~/.ssh/id_rsa.pub host_machine
However,
if a Linux server runs the SSH deamon on a non default port (default is 22),
you have to specify the port with option -p port.
In addition,
the host machine and the port options must be in quotes
(either single or double quotes),
otherwise,
you will get an error message.
Suppose sshd runs on port 323 on host_machine,
the following command copies the ssh public key to it.
ssh-copy-id -i ~/.ssh/id_rsa.pub "host_machine -p 323"
You can of course SSH into the server
and add your SSH public key(s) into the ~/.ssh/authorized_keys file manually.