For changing line space in the text, I will recommend two methods in word;
How to Change Line Spacing in Word by Design
1- Click on the Design tab.
2- In the “Document Formatting” part, click on the “Paragraph Spacing”.
3- There are some options for you to choose for line spacing.
If you want to change the paragraph spacing according to your desired you can follow this method.
Click on the “Custom Paragraph Spacing”.
Click on the Set Defaults tab.
In the Paragraph Spacing part choose your desired space.
Click on Ok.
How to Change Line Spacing in Selected Text.
1- Select the lines which you want to change the space between them.
2- Click on the Home tab.
3- In the Paragraph part, choose “Line and Paragraph spacing”.
4- Choose your desired spacing here.
For the more precise setting
Click on the “Line Spacing Options”.
In Paragraph dialogue, click on the “Indents and Spacing” tab.
In the Spacing Part
In the “Before and After” part, you can assign the paragraph space between the before and after paragraph.
Also, you can specify the space between lines in the “Line Spacing” and “At” part.
If you want to add this setting to whole the text you can:
Click on the “Set As Default” key.
Choose “This document only”.