Allowing password login will undermine the safety of server, so instead we can set up SSH login for each user.

The important point is that:

• for every user created on the server, each of their ~/.ssh/authorized_keys needs to be set up to include local machine’s public key.

To add authorized key to your server, SSH in as root user on server:

$ su your_user
$ mkdir -p ~/.ssh
$ nano ~/.ssh/authorized_keys

Copy the content of your local machine’s public SSH key and paste it into this file.

Reference: here or bottom of here.