The difference between a PCB and a PCBA is that a PCB is a bare circuit board, whereas a PCBA is a finished circuit board, by finished we mean a PCB with all of its components mounted.
A PCB (Printed Circuit Board) is a flat board made of non-conductive substrate materials with layers of copper circuitry placed internally or on the external surface.
A PCB’s purpose is to connect electronic components to create a PCBA.
PCBA stands for Printed Circuit Board Assembly, the term can be used to refer to the PCB with mounted components or the assembly process itself.
When referring to the assembly process, we’re talking about the action of making the plain board go through a THT or SMT soldering process
Once a PCB becomes a PCBA, it can perform all the electronic functions it was designed for