Let me have a shot at this.
The Anglican Communion is made up of 38 self-governing, independent Anglican jurisdictions, which arose primarily out of the colonial expansion of Great Britain. Their origin was thus in the Church of England, which was originally all that was meant by “Anglican”. But they have no formal affiliation with the CoE now, save by virute of being “in communion” with the Archbishop of Canterbury, which is the formal definition of the offical Anglican Communion. Not all Anglicans are part of this communion. I’m not, for example. The member church of the official Anglican Communion in America is the Episcopal Church. I could name a lot of the other jurisdictions but to find all 38, try a google.
It is the Church of England, not the Anglican Communion generally, that considers the Sovereign as the supreme Governor of their Church (the term is Elzabeth I’s; Henry had called himself the Supreme Head). I occasionally find folk who think that Anglicans generally burn clarified butter before images of the Queen, but it is not so. She is titular head of the Church of England, by act of Parliament, not of the entire Anglican Communion. In similar fashion, the Archbishop of Canterbury is the primate of the Church of England. Wearing another hat, he is titular (that is nominal) senior prelate of the Anglican communion. He has no authority over other bishops, outside the CoE, or over other Anglican jurisdictions, other than what he can manage through politics and persuasion. He is not an Anglican analog to the Pope.
Anglicans don’t excommunicate. It would be a good idea to do so, in many cases, but that’s not how things are set up. A member jurisdiction could be expelled (theoretically) from the Anglican Communion (when ice skating is an Olympic sport in Hell) but that’s about it.
Generally, the Anglican Church is not in communion with the RCC
because, inter alia, it takes two to tango.
GKC
Anglicanus Catholicus