Changing color of text in html export from org-mode

You can use a macro:

#+MACRO: color @@html:<font color="$1">$2</font>@@

* This is a test

This is a sample sentence in normal text color.

{{{color(red,This is a sample sentence in red text color.)}}}

{{{color(green,This is a sample sentence in green text color.)}}}

with the limitation that the second argument cannot contain a comma (and maybe some other characters).