The best suitable app for chatting with friends regularly is WeChat. Using WeChat app we can do voice chat, video chat and also group chat. 
More than 400 million people worldwide are utilizing the free services provided by WeChat app.
Android users can get WeChat from Google Play. BlackBerry users can obtain WeChat from App World
Do you have many friends circle? If so, you must know about Circle app which is special for android users. After installing, by making a local network we can know wherever the friends happened to be.
We can install Circle app freely from Google Play and we can use it together with Facebook.
iPhone users can install Circle app freely from iTunes
For some important topics if notes from the subject books is to be taken by scanning with smartphone camera, we can use ‘CamScanner App’.
Scanning with camera, those can be saved immediately in PDF format. To save scanned documents in the cloud storage, there is facility to upload them into Google Drive, Box.com, Evernote and Dropbox. If free version is used, it is ad-supported and a watermark will come with scanned documents. Android users can install CamScanner from Google Play
Apple users can install CamScanner Free from iTunes
There is another wonderful app named ‘Genius Scan+’ that turns any smartphone into a scanner. Using Genius Scan+ multiple pages which are scanned it merges into one single PDF or JPEG file. This scanner app is suitable platform for scanning and saving more pages at a time.
Get Genius Scan+ Android App or Genius Scan Windows Phone App or Genius Scan+ for iPhone and iPad.