How to set Flutter Text line space?

It looks like you looking for the height property of the TextStyle class. Here is an example:

Text(
  "Some lines of text",
  style: TextStyle(
    fontSize: 14.0,
    height: 1.5 //You can set your custom height here
  )
)

There are 2 properties you can set

Text("Hello World", style: TextStyle(
  height: 1.2 // the height between text, default is null
  letterSpacing: 1.0 // the white space between letter, default is 0.0
));