in termux 
wiki: https://wiki.termux.com
community forum:  https://wiki.termux.com/community

search packages:    pkg search <query>
Install a package:    pkg install <package>
Upgrade packages:    pkg upgrade
Learn more:    pkg help

Packages can be upgraded:    apt list --upgradable


***   ssh installieren
z.B.
   pkg install dropbear
or
   pkg install openssh