Unlike stb_easy_font which handles \n, with stb_truetype only the x position is advanced automatically. Glyph kerning and line breaks must be done manually. It is a low-level solution, but it's very powerful. You have access to the full range of glyph metrics and kerning information. High quality text layout is possible, but it does take some work.
For a higher-level solution, see NanoVG. E.g. nvgTextBox supports line breaks and uses stb_truetype internally.