I am summarizing several chat sessions. In one session, I was told a through via connects to all layers. In another session, the tech said if I want a signal to go on an inner layer, I need to use a buried/blind via and not a through via.
I’m not surprised about the confusion 
Use as an example, a multi layer board with an outer top and outer bottom copper layer as well as several internal copper layers.
A Via extends from the outer top copper layer to the outer bottom copper layer. It may or may not connect to internal layers.
A Blind Via extends from EITHER the top OR bottom copper layer to one or more internal copper layers. It only goes part way through the board, but is connected to ONE outside layer.
A Buried Via extends from an internal copper to another internal copper layer, MAYBE passing through and maybe connecting to several other internal copper layers. A buried via cannot be seen from, and will not connect to either outside copper layer.
An annular ring is the name given to a round pad surrounding, and connected to, any type of via.
If you want any sort of via to connect to a track on any layer, an annular ring is placed around the via on the layer needing connection to a track. If no connection to a via is required on a layer, an area with no copper is left surrounding the via.
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It suggests that you haven’t seen:
What is the first what google finds for ‘PCB via’.
And, it’s worth understanding why blind / buried vias are more expensive.
With standard vias, all layers are etched, and the board is laminated together, then holes are drilled, and the entire board is through-hole plated.
With a blind or buried via, some layer pairs need to be etched, drilled, and plated before the board is laminated. Then the laminated board is drilled again and plated for the standard vias.
This multi-step process is significantly more labor-intensive and error-prone (the multi-step drilling makes positional errors more likely).
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