Pictures on computers come in two flavours: *bitmaps* and *vector* pictures. For a quick idea of which is which, let's say that bitmaps are usually edited with softwares like photoshop (or gimp if you use free software), and vector pictures are edited using softwares like Adobe Illustrator (or Inkscape). Most softwares can display and read bitmaps, so they tend to be easier to share. Their main problem is that you can't zoom well on them. A bitmap fit for screen display will probably print poorly. However, sharing vector pictures is quite difficult (for no good reason, but it's a sorry state of affairs), so you might end up sending high-resolution bitmaps for printing.
To export a bitmap, choose the “File/Export As/Export as Bitmap” menu entry.
You can export a jpeg or png version of your text. If no text is selected, the whole text will be rendered. If there is a selection, only the selected text will be drawn.