What is inline editing?
In-line editing lets you make quick changes without going to a new page. You can change daily budgets, ads, keywords, placements, and bids. If a cell is editable it will show a pencil icon. Click the cell to edit its value.
How do you edit inline?
Go to Setup and search for User Interface. You can also go through the path of Platform Tools > User Interface > User Interface or Build/App Setup > Customize > User Interface (last option). Select Enable Inline Editing and Enable Enhanced Lists then Save.