Production Part Approval Process (PPAP):
PPAP is production approval process, which provides the customer with the exact production intent from supplier. The latest 4th edition was released in 2006. As per AIAG, there are 18 documents that form a PPAP.
The creation/ requirement of these documents are decided based on the needs of each customer. If you are manufacturing low cost products or very sensitive part, you may submit all these documents. It will also depend on the customer demand, if the demand is low and cost of part is more it is not possible to submit a master sample.
If it was so, we will ask Ford/ GM/ Chrysler to submit a PPAP to us and would have got our desired car as Master sample.
Level of submission:
First you will have to know, your customer requirement. What level does your customer need?
There are five levels of submission as per AIAG guidelines, which can again be modified according to customer need.

Level 1:This is request to submit just Part Submission Warrant (PSW).
Level 2: This is request for PSW, product sample and limited supporting data.
Level 3: This is PSW, product sample with all supporting documents .(Default)
Level 4: This PSW with all requested data by customer.
Level 5: The PSW, product sample and all supporting documents to be made available at manufacturing site for  
            customer's review.

The default level of submission, if not specified is Level 3 PPAP. This means all documents have to be submitted.
Level 1, is generally for suppliers who have been supplying, same/ identical part without any customer concern.
Level 2 is when you have made slight modification, which does not change the process of manufacturing.
Level 3: This is for a new part/ new supplier with no previous supply.
Level 4: This is mostly for part undergone considerable design changes.
Level 5: This is not suppliers with lot of previously known issues/ if the supplier is not good in establishing quality system.
Any way, the whole point is, these are all suggestive documents. You and your organization will have to modify them based on your needs and suitability.

The documents are listed as following:
1) Design records.
2) Engineering Approval.
3) DFMEA.
4) Process Flow Diagram (PFD).
5) PFMEA.
6) Production Control Plan.
7) Measuring System Analysis.
8) Dimensional Results Report
9) Material Study/ Records of material
10) Initial process study.
11) Qualified Lab documents
12) Appearance Approval Report (AAR)
13) Sample production parts.
14) Master sample
15) Checking aids
16) Customer specific requirement
17) Part submission warrant
18) Engineering change.