Inline editing provides a way for users to mass edit records from a list view. This can sometimes be faster than performing a mass update by way of an exported report. Although this isn't always the solution, it can be much more efficient than opening each individual record to edit a value.
Before users can start inline editing, the option must be turned on by a system administrator by going into Setup > User Interface and checking the box for “Enable Inline Editing”:
Once this setting has been enabled in your org, follow along with the video below to start inline editing from the list view.
There are some limitations around inline editing as not all field types are supported. Please refer to this help article for more information.