My opinion is that every Christian should know precisely what the Godhead is, because the explanation is given to us so succinctly.
Just two verses are all that is required to fully understand...
Hebrews 11:3 - "Through faith we understand that the worlds were framed by the word of God, so that things which are seen were not made of things which do appear."
The above verse is teaching us that the Word of God is what creates the reality we live in. It is like software generating an image on a computer screen. Moreover, the Word of God is 'invisible' to us. Everything that we see in this Universe is made of something we cannot see. The Word of God is the 'Invisible God'.
Now that we have established the basics, we can move to the next verse...
Romans 1:20 - "For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse"
Again, the 'Invisible Things of Him' is the Word of God that manifests the physical Universe we exist in. Yet, the verse is teaching that the invisible Word of God is somehow 'clearly seen'. Is that a contradiction? No, we see the Word of God through the 'things that are made', i.e., ordinary Matter.
The word 'even' in the above verse is a unique word in the KJV. It is the same as if I were to say, 'in other words'. Thus, the verse would be understood as saying...
"...things that are made, in other words, the Godhead'.
Simply put, the Godhead is what things are made of. This is precisely what the two verses above are teaching, yet for some reason Christians cannot wrap their heads around the profundity of it all. The irony is that the verse ends with the statement 'they are without excuse', as if to say that One must really be ignorant to not know something so simple and basic.