OpenSSH is probably installed by default by every available Linux distribution.

However, the packaged versions are not always updated frequently enough to include the latest feature and security fixes.  You may also need to update a production server that runs an older distribution for which you can’t find a suitable package. In either case, installing from source may be your best bet.

A procedure for installing OpenSSH from source code is available here.

OpenSSL is an Open Source toolkit installed, and used extensively by all kinds of software running on Linux systems.

If you find your distribution is slow to provide the latest feature and security updates, you may want to consider installing the latest version from source code.

A procedure for installing OpenSSL from source code is available here.