I was just curious to know if I need to enter both the global command "ipv6 unicast-routing" and the interface command "ipv6 enable" to enable routing on a router? I am just trying to figure out what the difference is with the two commands and if/when it's necessary to use one or both commands. Thanks in advance!
You only need ipv6 unicast-routing.
ipv6 enable enables IPv6 processing on an interface that has not been configured with an explicit IPv6 address. If you manually configure an IPv6 address under the interface, it automatically enables IPv6 and creates a link-local address as well.
Without ipv6 unicast-routing IPv6 datagrams can't be forwarded.