For any version of MS-Word from 2010 and later, this would likely be the easiest method:
1. Do a Select All (CTRL+A) if you want the indent to apply to all paragraphs, or select the range of text where you want the first line indents to be applied.
2. ALT+H,PG [Home Ribbon, open Paragraph Dialog].
3. ALT+S, throw focus to the Special dropdown in the indentation section, select First Line from the dropdown.
4. The "By" edit box will automatically be prepopulated with 0.5 inches. If that's fine, jump to step 5, otherwise, edit the box to adjust the indent depth to what you want.
5. Activate the OK button on the Paragraph dialog.
All of your first lines on all paragraphs will now be indented by the amount specified.
Brian - Windows 10 Pro, 64-Bit, Version 2004, Build 19041
The purpose of education is not to validate ignorance but to overcome it.