Ancap may not have involuntary taxes, but it will have relatively involuntary costs for the same things that taxes go to. You could live without police, but you're probably going to want to have police, so you end up voluntarily paying for police just like under a State. The hope is that there are more choices at lower cost and not one entity in charge of policing though (or at least competition is allowed).

Ancap may not have government-imposed regulations, but there will be only so many companies that provide the things that government does (like courts) and they will "govern", in a sense, creating the best rules they can, and people will follow along.

Rules will be agreed upon almost universally, like that things like trespassing, theft, etc. are unacceptable on any property, so you'd see a lot of standardization of rules that spread to each property.

So a structure emerges that ends up looking very much like government (just like a body is composed of individual cells but makes up a full unit, you could almost call ancap a kind of "State" or "UnState" really). This is why left libertarians and ancoms sometimes consider ancap-ism to not be a form of anarchy, because it ends up looking basically like governments we see today.

Companies that form in often have a CEO or central leader, with a board of directors. Someone remarked that this community forum should have no leaders as if this was "anarchist", but businesses form with a head moderator (like the CEO) with sub-moderators (like the board of directors) and then the other workers in the group (like posters here). It very much ends up looking like things in a "State", and this comes about naturally in "capitalism".

I'd argue ancap could end up looking very much like what we have now, only possibly with more options (sometimes people argue what ancap would look like is a mysterious unknown, or that it would look "very" different).

I think this is important to realize because then ancap-ism is not seen as being so different but is more accessible to show to the average person, as well as being actually workable because it's like our already existing conditions (only improved upon, is the hope).