There are lots of functionalities that you can use to update data as bulk.
Some of them are:
1) Update via writing jobs
2) Update via Data Management
3) Update via Excel Upload
But there is also one that is really easy if you want to update data of a field on a form.
All you have to do is select the data you want to update and....
Use "..." and select "Edit Selected rows"
Select the field(s)
And "Apply"...
That easy :)
