change a font size in articles

hello thanks for the answer, but my question was another, in which class do I find the default: ("tahoma and px 9) because when I insert a new article it puts this data in default and I would like to change it
thank you

Hello,
write your text and the font is based on css and has nothing to do with the shown formation of the editor.
And btw it has nothing to do with the template. Its more like a editor joomla question.