hyphen area？What does this mean? What is the use?

[dublove]

What does this mean? What is the use?
I tried several values, and it seemed that nothing changed.

[Barb Binder]

Hyphenation Zone Specify the amount of white space allowed at the end of a line of unjustified text before hyphenation begins. This option applies only when you’re using the Single-line Composer with nonjustified text.

—https://helpx.adobe.com/indesign/using/text-composition.html

I can see you are using justified text text and InDesign defaults to the Paragraph Composer so please pay attention to the italicized text. 

~Barb

[dublove]

Thank you ~
I have read it, but I still can't understand.
Do you have example files to share?
There are files with "Hyphenation Zone" and no "Hyphenation Zone" comparison.

[leo.r]

Thank you ~
I have read it, but I still can't understand.

By @dublove

Your text is using Justified alignment:

Hyphenation Zone does not apply to this alignment.

It only applies when you use the Single-Line Composer

AND non-justified text, for example left-aligned:

[dublove]

Here are more accurate instructions

https://clagnut.com/blog/2395/

The article is recommended to use percentage, does ID support 0.8?

[leo.r]

The article is recommended to use percentage, does ID support 0.8?

By @dublove

Once again, your text is using Justified alignment and, therefore, Hypenation Zone has no affect on it.

Do you have any text that satisfies the following two conditions:

-Uses the Single-Line Composer,

AND

-Non-justified alignment (left, right etc?)

[James Gifford—NitroPress]

https://helpx.adobe.com/indesign/using/text-composition.html

It sets the width allowable for empty line space if words are hyphenated on that and adjacent lines. Adjusting this prevents awkward breaks that leave some wide area at the end of a line blank.

[Mike Witherell]

I like to describe it as how much "saw-toothing" you will allow. I like to set it to .25 inches on rag-right body copy.

[James Gifford—NitroPress]

Excellent visualization.