HI
You can remove T3 logo from backend
Regarding the copyright you should purchase a copyright removal license
<blockquote>
JATC Standard / Personal members need to purchase copyright removal to change the footer notice but cannot rebrand the product / file info, whereas, Developer members are free to remove copyright or rebrand the products.
With Copyright removal you can remove our footer “Designed by JoomlArt.com” and changed it to “Designed/Powered by YourCompany”.
The Copyright Removal fee structure is as follows:
Copyright Removal for 01 domain: USD40
Copyright Removal for 02 domain: USD70
Copyright Removal for 03 domain: USD90
</blockquote>