Where to add <NOADS>?

[Athorn]

My webhost hxxp:www.zendurl.com [nonactive] recently added ads to all the pages of my forum, stating that if I don't want them, I can put the zendurl tag <NOADS> on any page I wish, so their firewall can detect it and remove the ads.
Where do I add this tag in the SMF forum? Should I add it in a single file (a php file?) or in more files? Which file would it be, and where do I put it best so it doesn't mess up any coding?

Thanks for your help!

PS. The forum is just an ordinary SMF 1.1.2

[Dragooon]

I think it can be better to ask your host But you can try Index.template.php