If I try to install libssh-devel or libssh-devel I am unable to locate the package. I have updated and upgraded with apt so that all packages are now up to date, but still just get left with unable to find package.
On Kali, like other Debian derivatives, you can use
apt search to look for packages.
apt search libssh will tell you that the package containing the development files for
apt install libssh-dev
will install the files you need.