Mobile Spying or Monitoring are such features of applications which let you to view activities of Mobile of person. Spying including Live Location tracking or person, view past, recent, live activities of mobile phone. For this Mobile Spying application need to be installed on the Mobile you want to monitor or track.
You should only spy over the mobile phones for which you are responsible, Such Spy applications are generally available to download on website of such service provides, some spyware application maker send you spy app by email.
It is easy to install the Spy application if it is availble to download from a webpage which is accessible without any login like in SpyBrad you can download and install without any hassle from Download Page
A Spy software collects logs from mobile device and uploads them to your account with them where you can login and access the data. Some Spy application upload the data peridiocally or some do it instant like SpyBrad.
Spying over a rooted android phone gives access to much more logs as a rooted device expose all its data to third party apps and they can read whatever they want. So rooted phone let you monitor many more features like rebooting mobile, viewing mobile screen remotely, capturing Social Media chats with media like WhatsApp, Instagram etc.