Based on the search results provided, here are the key steps to set up a user with SFTP access only, without shell access:

1. Create a new user account for SFTP access, for example "mysftp":[2]
  ```
  adduser mysftp
  passwd mysftp
  ```

2. Create a directory for the SFTP user to access, for example "/var/sftp/uploads":[2]
  ```
  mkdir -p /var/sftp/uploads
  chown root:root /var/sftp
  chmod 755 /var/sftp
  chown mysftp:mysftp /var/sftp/uploads
  ```

3. In the SSH server configuration file (/etc/ssh/sshd_config), add the following settings:[2][3]
  ```
  Match User mysftp
      ForceCommand internal-sftp
      PasswordAuthentication yes
      ChrootDirectory /var/sftp
      PermitTunnel no
      AllowAgentForwarding no
      AllowTcpForwarding no
      X11Forwarding no
  ```
  This restricts the "mysftp" user to SFTP access only, without shell access.

4. Restart the SSH service to apply the changes:[2]
  ```
  systemctl restart sshd
  ```

5. Verify the user can only access SFTP and not the shell:[2]
  ```
  ssh mysftp@localhost # Should show "This service allows sftp connections only"
  sftp mysftp@localhost # Should allow SFTP access
  ```

The key points are to create a dedicated SFTP user, restrict their access to a specific directory, and use the SSH configuration to force the use of SFTP without shell access. This approach allows granting limited file transfer access without full system access.[1][2][3][4][5]

Citations:
[1] https://unix.stackexchange.com/questions/503312/is-it-possible-to-grant-users-sftp-access-without-shell-access-if-yes-how-is-i
[2] https://community.hetzner.com/tutorials/add-sftp-only-user-no-ssh-access-on-centos-7/
[3] https://askubuntu.com/questions/534675/restrict-users-to-sftp-access-only
[4] https://thunderysteak.github.io/sftp-user-chroot
[5] https://www.digitalocean.com/community/questions/trying-to-setup-a-sftp-user-with-limited-access