In order for JLC to accept pick and place files from Altium, some changes need to be made from the default. The following was taken from this Phil's Lab video
Inside of the generated Pick and Place CSV (opened with your editor of choice, I will be using Notepad++), the following is generated:
Everything until the header line can be deleted:
The headers "Center-X(mm)" and "Center-Y(mm)" must be replaced with "Mid X" and "Mid Y" respectively:
And then Find and Replace all "TopLayer" with "Top":
