Wordpress Editor

We are an online education provider looking for a Wordpress Editor to edit our website pages :

• Change H1 and H2 text colour, Body text size to 14 px - 26 pages
• Change background colour of certain button on certain pages - 4 pages out of given in 26 pages in point 1
• First sample work for a sample page will be analysed, if we find it ok, we move ahead for rest of pages