Convert Single Cell Text line Into Multiple Line

1. Go To The Cell That Contain The Overflow Line.
2. Then Select Multiple Row + Column Including The Cell Having Overflow Line As per your Idea That It Will Look Good Or Will Be Fit Accordingly.
3. Then Go To Home Tab.
4. Then Go To Fill. (Shown In The Image Below)
5. Then Click On Justify.
6. Note: The Text Written in The Cell Has Nothing To Do With This Rule. It Is Just For Demonstrate.
7. Excel Version : 2016
8. Please Check The image Below.

TO CONVERT BACK AS IT WAS ORIGINAL PLEASE CHECK THE STEP AND IMAGES SHOWN BELOW.

1. Go To The Original Cell That Was Having Overflow Line Before.
2. Then Select Range Row + Columns Line As Per Your Requirements
3. Then Go To Home Tab.
4. Then Go To Fill. (Shown In The Image Below)
5. Then Click On Justify.
6. Please Check The image Below.