Question

where in the nec® does it provide information material and examples that might be considered helpful but is not mandatory?
tables
informative annexes
introduction
informational notes

Explanation:

NEC (National Electrical Code) Informative Annexes offer helpful info/examples but aren't mandatory. Tables often have mandatory data (e.g., wire ampacities). Introduction gives general code - related info (not specific examples/helpful material as main focus). Informational Notes are within code articles (more inline, not comprehensive like Annexes).

Answer:

Informative Annexes