When your customer requires a PPAP, they will frequently note a submission level. The exact elements that need to be submitted to the customer will depend on the part and the requirements in the purchase order. According to the AIAG PPAP manual, all elements should be completed. The PPAP levels indicate which documents need to be submitted to the customer, and which can simply be retained by the manufacturer.
Level 1 - Part Submission Warrant (PSW) only
Level 2 - PSW with product samples and limited supporting data
Level 3 - PSW with product samples and complete supporting data
Level 4 - PSW and other requirements as defined by the customer
Level 5 - PSW with product samples and complete supporting data available for review at the supplier's manufacturing location
A few notes on the PPAP Levels:
A Level 3 PPAP requires that you submit all the documentation of a PPAP except elements 15 and 16, which are the master sample and checking aids.