How do I Convert time/date format? I have created a View and added a filed Date. This Field have 4 type of Formatter 

1) Date and Time
2) Time Ago
3) plain
4) Services Raw

If I select First it give HTML tags in output and if select 3rd or 4th it give output like these numbers "1439393400"

I need the simple date in output without any HTML tags. Please tell me how I can get rid of HTML tags if I select first option. If its not possible then how I can convert the output which I get from Plain Formatter so that I get simple date not these number.
For creating a new date format to be used in views:-

Go to yoursite.com/admin/config/regional/date-time
And create the new format.

Now, Go to the view you're working on, add date field, change its format. Yes, it's as simple as that.

Plus: You can use Date module, it has got amazing features.