You're thinking to hard about this.
Using a DVM meter , it doesn't tell you if it's a biasing voltage or a normal DC voltage , so how can you know or tell?
1. A DC voltage is a DC voltage,
irrespective of how it it used. Your DVM cannot and
will not ever tell you how the voltage value it is displaying is being used. That is for you to determine.
Is every Biasing voltage a DC offset voltage...
2. Generally, yes. However, there are AC biasing voltages used, for instance, in tape recorders for tape erasure puposes. But for the moment, forget about those. Think of biasing as purely a DC value.
...with a AC or DC waveform riding on top of a DC voltage?...
3. Look up the definitions for DC and AC. By defintion, DC
is not a waveform. But, yes, an AC waveform, with DC biasing, is riding on top of (or superimposed on) the DC bias level.
... it this the only type of biasing voltage there is
See "2." above.
But how do you know when looking at a schematic or at the nodes on the schematic that it's going to be a Biasing voltage and not a DC voltage
Once again, you must discard the notion that a "bias" voltage is somehow
different from a "DC" voltage.
BOTH are defined as DC.
How they are used is what's different in the circuit. That's all.
As for indentifying, from a schematic, a biasing circuit, you must first understand all of the above.
If I may ask, did you visit the site I posted concerning "Biasing"? If so, may I ask you to tell us, in your own words, what did that definition tell you?