First, you need to understand what is PCB? PCB also known as printed circuit board, is one of very important electronic component, with the support of electronic components, then it is a electronic component and a carrier for electrical connection. They are generally made by electronic printing, so they are called printed circuit boards.
So what is PCBA? PCBA=assembly of PCB. That is, various electronic components are assembled on the circuit board by a surface insertion process. Then, next to the box assembly, the assembled PCB will be assembled with the outer casing and finally form the finished product. That is to say, the PCB bare board is the entire process that needs to pass the SMT upper part and then pass the DIP plug-in, referred to as PCBA. This is a common way of writing, and the standard way of writing in Europe and America is PCB'A, which is added with a slanting point. PCBA is the PCB with the film attached.