Fusion will generate a 3D simulation of your board, helping you visualize how it will look when you solder it together. Unfortunately, only a fraction of the parts in the fusion library are associated with a corresponding 3D model. When Fusion can't find a corresponding 3D model for a part, it will substitute in a box for that part. While this is not ideal, the tool is still very helpful, and going through this process is recommended.
With the DESIGN menu active, choose the option:
Push to 3D PCB.
You will see a menu letting you know which parts are available and which parts will be substituted with boxes. In this example, all the parts are available as 3D models. Press Push to see the 3D model.
Once you've previewed your board (assuming you're happy with it), it's time to export the file for production. Click on the MANUFACTURING menu and choose the option CAM Processor.
Make sure to click Export as ZIP followed by Process Job
Look for the Job processed successfully! Dialog and press OK.
Save the file somewhere easy to find on your computer.
Go to JLCPCB https://jlcpcb.com
and drop your ZIP file on Add Gerber file.
Inspect your file. You can look at the Top and bottom of the PCB.
If it looks good, you’re done! (we won't order this test file).
If anything looks wrong, head back to Fusion to redesign, re-export, and preview again.