To insert text in Geogebra is relatively simple with “Insert Text”-button. But, if you want better looking text, så kan det betale sig at kende til LaTex-formler. LaTeX er en kodning, Allow to develop mathematical expression. Det lader sig gøre på hjemmesider, but also in GeoGebra.

See, e.g., the following:

\sqrt{a ^ 2 b ^ 2}

now is named

How to do:

You can try out the following website:
http://www.codecogs.com/latex/eqneditor.php