I have made the below changes -
1. pi@VOXELSTUDIO:/usr/local/Repetier-Server/etc $ sudo cp RepetierServer.xml /var/lib/Repetier-Server/www/
2. pi@VOXELSTUDIO:/var/lib/Repetier-Server/www $ sudo mv RepetierServer.xml RepetierServer-extra.xml
3. pi@VOXELSTUDIO:/var/lib/Repetier-Server/www $ ls -ltr
total 16
-rw-r--r-- 1 root root 13208 Apr 23 00:42 RepetierServer-extra.xml
4. Updated the above file and added the branding tag (as highlighted below)
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<server>
<installation-directory>/usr/local/Repetier-Server/</installation-directory>
<storage-directory>/var/lib/Repetier-Server/</storage-directory>
<default-language>en</default-language>
<port>3344</port>
<https-port>3345</https-port>
<disableIPV6>false</disableIPV6><!-- setting to false can cause problems with external access -->
<!-- To prevent clickjacking we should disallow embedding in iframes -->
<allow-iframe-embedding>false</allow-iframe-embedding>
<logging>true</logging>
<backlog-size>1000</backlog-size>
<!-- how many files should be stored in the last printed files list -->
<last-printed-files store="10"/>
<max-log-files-per-printer>5</max-log-files-per-printer>
<update-info-url>http://download.repetier-server.com/files/server/debian-armhf/updateinfo.txt</update-info-url></div><div> <printer-frontend-url>/modules/front2/www/app.html</printer-frontend-url>
<web-frontend-url>/</web-frontend-url>
<custom-ssl-certificate-store></custom-ssl-certificate-store><!--If you want to add your own SSL certificates, please enter here the directory where your certificate is stored. Note: only certificates with the extension .pem will be considered-->
<unixSocket></unixSocket><!-- path to unix socket for socket communication - leave empty to disable feature -->
<features>
<branding>
<shadow-www-directory>/usr/local/Repetier-Setup/www/</shadow-www-directory>
<branded-name>VOXELSTUDIO</branded-name>
</branding>
<!-- ========= Control which config options appear in global settings for whom ========= -->
after saving this file it still did not update the branding