The Shifting Margins
Google Docs attempts to anticipate your formatting needs. A common behavior occurs when you manually hit the “Tab” key to indent the first line of a paragraph. Docs registers this action and often assumes you want this specific formatting applied to the rest of the document. Therefore, when you finish that paragraph and hit the “Enter” key to start a new one, Docs automatically indents the new paragraph as well. If you only wanted to indent that single specific line (perhaps for a blockquote or a specific stylistic choice), you are forced to manually hit backspace on every subsequent new paragraph to break the formatting chain.
Resetting the Alignment
To maintain manual control over your document structure and stop Google Docs from automatically indenting new paragraphs based on your previous actions, you must reset the paragraph styling definitions.
Google Docs handles this via its “Normal text” style definitions rather than a simple toggle switch. If Docs is currently auto-indenting your new paragraphs, type a few words on the new, incorrectly indented line. Now, press the Backspace key (or Shift+Tab) until that specific line is perfectly flush with the left margin (0.00 on the ruler). Once it looks correct, click and drag your mouse to highlight that newly corrected text. Now, look at the top toolbar and click the dropdown menu that currently says Normal text (it is located just to the left of the font name). In the dropdown menu, hover your mouse over the words “Normal text” to reveal a secondary slide-out menu. Click on Update ‘Normal text’ to match. By doing this, you are redefining the baseline default for the document to be zero-indentation, stopping the automatic shifting on subsequent lines.