When working with the word document, all the lines by default will align left. However, you can indent the first line of each paragraph with the steps below:
Step 1: Select the paragraphs or the whole contents in the word file if you want to indent all the file;
Step 2: Click the "Home" tab from the ribbon (or the "Layout" tab);
Step 3: Click the right-bottom corner in the "Paragraph" section;
Step 4: Under "Indentation" section in the "Paragraph" window, select "Fisrt line" in the "Special" box and type the number you are going to indent in the "By" box (e.g., 0.5");
Step 5: Click "OK" to finish, and you will find the first line of each paragraph is changed.
If you want the first line of each paragraph is hanging, please select "Hanging" in the "Special" box.
Here is the word document after you select "Hanging" for the first line of each paragraph.
Please see how to increase indent from both sides if you need to.