Your question is unclear. Assuming you mean the size and shape of the PCB as defined by the board area: [https://docs.easyeda.com/en/PCB/Board-Outline/index.html](https://docs.easyeda.com/en/PCB/Board-Outline/index.html)

Hello ; If you are talking about the PCB size in our JLCPCB ordering web-page then let me inform you that this is automatically set once you upload the GERBER file to our system, this data is uploaded through the board outline file, or you can change it through the size parameter as it shows the below image :  If you mean the PCB design size then please specify the design tool that you are using and we recommend that you change the post topic to "PCB Layout" <br> <br>