TRichView.com

1,can i set TAB char width in RichViewEdit?
2,i want to addNL with CR or LF, what cai i do?

You cannot define tab width, but you can define tab positions.
See
1) TRVStyle.DefTabWidth,
2) Each paragraph may have each own tab positions: TRVStyle.ParaStyles.Tabs collection

For adding text with CR+LF, use AddTextNL

but i don`t want to begin a new line,maby is append some text and with CR+LF.

Rules are the same, if ParaNo parameter =-1, text is added to the same line.