how to change only one text font

there is a simply method for change only one text font?

What do you mean? If you want to change the font for one text item, that's pretty simple

screen.setFont(new_font)
screen.drawText(...)
screen.setFont(original_font)

thanks but before loading the font that I have selected it shows me the original font for a few seconds

In that case please check the solution here :

https://microstudio.dev/community/bugs/drawtext-draws-different-size-text-after-first-draw/153/

=)

Sorry I'm so late, but the reason is because the font isn't loaded. I would recommend loading all the fonts you want to use in init with screen.loadFont(font_name), and then changing to whichever you need, so that they are all pre-loaded. Otherwise, you can check if a font is loaded with screen.isFontReady(font_name)