The answer should be: they don't. In an ideal world, users would never need to be aware of the lower layers of the protocol stack, and they certainly should never have to see a hexadecimal number, or even be aware that they are using IPv6. The goal of a network designer or operator should be to make this true.
However, it's unlikely that this will always succeed. It's likely that if a user ever does see something specific to IPv6, it's probably at the worst possible time: when there is a fault or a system configuration issue. That is exactly when the user is either reading on-line help information, or in contact with a help desk. It is therefore recommended to review any documentation you provide to users or to help desk staff to make sure that when IPv6 is mentioned, the information is complete, correct and up to date. It's also important that configuration tools are designed to avoid or minimize any need for users to enter IPv6 addresses by hand.