can I charge battery at the same time as using it if it is the new usb c pd
simulate this circuit &ndash; Schematic created using CircuitLab
Figure 1. A rough schematic.
As usual, the Amazon products don't come with proper datasheets and that's why we don't recommend them as a source of components.
The quote in your question is mine, I think, from someone else's question. What I am saying is that the battery can't be charging and discharging at the same time. Either current is going in or coming out. It can't be going both ways.
In Figure 1 it should be clear that if you have power in on the left and power out on the right that one of several things can happen:

If the output current required is less than the that which can be supplied by the input source then there is power available to charge the battery.
If the output current is greater than the input supply can provide then the battery must make up the difference and will be discharged.
If the battery is fully charged then the output will draw current directly from the input.

I've kept this very simple. In practice there will be a boost converter to step the battery voltage up to whatever the output voltage is supposed to be and it should shut the output off to protect the battery before it goes flat.