I could not find the tool "Easy custom labeling" in Plugin Manager.
My colleague can install the tool for QGIS in her PC but she uses Windows 7 while I use windows 10. Could anyone advise me how to get that tool installed for windows 10?
It seems that the EasyCustomLabeling tool is not listed in the plugin manager currently - this has been an issue for several people, as seen in this github thread: https://github.com/haubourg/EasyCustomLabeling/issues/20
To use the plugin, you can download the plugin at the official QGIS plugin repository: https://plugins.qgis.org/plugins/EasyCustomLabeling/
And then install it following the directions listed in this answer: How to Install QGIS 2.6 plugins offline