If you're looking to Download SFTP Server on your Chromebook laptop Then read the following guideline.

SFTP Server allows you to share / exchange files via the SSH File Transfer Protocol (also Secure File Transfer Protocol, or SFTP). * Note: ports below 1024 require macOS Mojave (10.14) or later. * Features • Secure file transfer • Built-in SFTP accounts (independent of the macOS accounts) • Per-user home directories • Simple and easy to configure • Supports popular SFTP clients such as FileZilla and WinSCP • Supports documents, photos, movies, apps, backups, folders and other files * Please restart the SFTP service after changing the configuration / the SFTP accounts. * The default document root points to "/Users/*username*/Library/Containers/net.langui.SFTPServer/Data/Documents/SFTPShare", you can press Command-G in Finder to go to the destination folder. * The log file is located at: ~/Library/Containers/net.langui.SFTPServer/Data/sftpserver.log