To indent the first line of a paragraph, put your cursor at the beginning of the paragraph and press the tab key. When you press Enter to start the next paragraph, its first line will be indented.
Tip: If you want to change indentation for paragraphs that have already been written, use the tab-key method on the first paragraph, as described above. Then put your cursor at the beginning of the next paragraph. Press Backspace and then Enter. Repeat the process for subsequent paragraphs.
First-line indent by default
If you always want first-line indentation, modify the Normal style:
Put the cursor anywhere in the paragraph.
On the Home tab, right-click the Normal style, and choose Modify.
Select Format, and then choose Paragraph.
On the Indents and Spacing tab, under Indentation, select First line.
Select OK again.
Note: If you always want first-line indentation whenever you start a new document, choose the New documents based on this template option before you select OK.