How can i create an About Us web page in moodle and apply the theme to it???
The easiest thing to do is to add a "Compose a Web Page" resource to the front page. The theme of the home page or course (depending on where the resource is) is automatically applied.
To do this on the front page (I have 1.9, The steps should be similar in 2.x):
1. Go to Site Administration>Front Page>Front Page settings
2. Select the Include a topic section option
3. Save the change
4. Turn editing on from the front page
5. Select the Compose a Web Page option from the Add a Resource drop-down box.
6. Create your page.
HTH,
Isaac
Alternatively there is the main menu block if you add it. You can add a page from there. If you don't want the main menu block showing you can get the URL of your page and then hide the bock itself and just link to the URL of your About us page in whichever way you like. In Moodle 2 it will appear in Site Pages in the navigation block.
Another alternative is to add a HTML block. Lots of ways and the page automaticaly inserts itself it to the theme, or the theme is automatically applied to the page - which ever way suits you. There are any number of whay you can change the appearance of your page, within the theme, if you want. Look at this page for v1.9 and this page for v2, and take control of your front page (should open in new tab/window).