A corrigendum is a correction of an error (mistake), especially a printing mistake.

An amendment is a <em>change</em>.  It might be a correction, but in most cases an amendment is not a correction of an error. It simply changes something.

Example of a corrigendum (correction):   "There's so much noise I can't here hear you."

Examples of an amendment to change something:  The Constitution says, "All persons at least 21 years old may vote."  Then an amendment to the Constitution is approved, which says, "All persons at least 18 years old may vote."

Corrigendum vs amendment

What is the difference between two words "corrigendum" and "amendment"?

Corrigendum is the thing that <em>is to be corrected</em>, something that requires correction, before it has been amended. 

If your question is as to the difference between correction and amendment, a correction is an amendment, whereas an amendment may or may not be a correction.