It is possible to set kmail to reply with indents for the quoted text ?

Are you referring to the ">" characters inserted by most mail clients on inline replies?

Yes, in the past i saw replies from some persons that they had an indent for the quote text of other messages. In fact yesterday i saw kmail putted a text that i quoted in my reply in a layout with indents instead of >. But i did nt see it anymore , i think that was happened accidentaly, or there is a setting that allow this type of quote ?

This is likely controlled by your template, and the type of email (plain text or HTML) being set. Please see your KMail settings, where you can configure your templates.