Use Wrap Settings and Auto Size to define how text should adjust within the boundaries of its parent box.
There are 3 different wrapping modes:
If you want the text to fit snugly inside the box, scroll to the Auto Size subsection to learn how to.
Starting version 0.5(50acd18), the text parameter
Width Settings was renamed to Wrap Settings to help avoid confusion. If you ran across warning messages, try recompiling the faulty blueprints.Wrap at Pixel Count
Breaks the text at a specific pixel count regardless of the bounds set by the parent box.
Wrap at Percentage of Parent Size
Uses parent widget as the limits for breaking text — this means that when the value is set to 1, the wrapping will consider the whole area; setting a value of 0.5 or 0.25, will correspond to 50% or 25% of the parent’s size respectively.
You can also input values higher than 1 to extend text beyond the parent’s size.
When the text being rendered cannot fit inside the bounding box it will overflow vertically.
IMPORTANT: Setting the wrap settings to
Percentage of Parent Size while having Size to Content turned on will create visual glitches. This is due to a circular reference, where the parent size is defined by the content, and the content size is defined by the parent.
It’s recommended to set the wrap settings to No Wrap or Wrap at Pixel Count when using Size to Content.
No Wrap
Results in the text not breaking at all.
This is ideal when you want to have the parent slot use Size to Content, meaning it can safely derive its size from the text contents.
Auto Size
The Use Auto Size option will force text to fill the maximum amount of space of its parent box by adjusting the letter size, taking into account any settings already determined on Wrap Settings.
Tip: If you want the text to fill the entire widget box, select
Percentage of Parent Size on wrapping settings and set the value to 1. 
You can also use the auto-size option on your Expressive Text Actors and have the text automatically adjust to fill the whole plane:
