Manners are basically learned behaviors, such as saying please and thank you or closing your mouth while chewing, that exist within the much larger societal code that is etiquette.
According to Emily Post, author of "Etiquette in Society, in Business, in Politics, and at Home," etiquette involves more fundamental things like being respectful and considerate.
On the other hand, manners change with the times, like keeping one’s elbows off the table. It used to be taboo but is now considered acceptable in most circumstances.
However, they’re similar in that etiquette provides a framework for ethical, respectful conduct while manners provide the actual rules for behaving properly.
While etiquette originally began as a series of elaborate rules to distinguish between upper and lower classes, it became more commonsensical as it filtered throughout society.
As that occurred, manners likewise transformed into more logical, less ritualized customs. They continue to be learned cues formed to meet societal standards.