Centroid file/Pick & Place File contains the information about where each component should be placed on the board, There're X and Y Coordinate of each part, as well as rotation, layer, reference designator, and the value/ package.

1. Bill of Materials (BOM)
The BOM(Bill Of Materials) is a list of all the parts which will be populated on the board. The information in the BOM must be enough to define each component, the information from BOM is very critical, must be complete and right without any mistakes.a complete BOM will reduce a lot of trouble in components,
Here're some necessary information in BOM: Reference number. Part number. Part value, Some extra information would be better, such as Parts description, Parts pictures, Parts manufacturing, Part link...

2. Assembly Drawings
An assembly drawing helps when there's trouble to find the position of all components in BOM, and it also helps for engineer and IQC to check and find the issues by comparing it with PCBs which are made, especially the orientation of some components.

3.  Special Requirements
If there're any special requirements which are difficult to describe, you can also show it in pictures or videos, It will help a lot for PCB Assembly.

4. Test and IC Programming
If you want your PCB factory china manufacturer to test and program IC in their factory, It's required for all files of programming, the method of programming and test, and the test and programming tool might be used.