Open **Tools → Styles** (**Ctrl+L**) to choose what participates in the comparison
and how the result appears. Comparison and display settings are in the same
Styles dialog. The exact controls available depend on the installed version.
If Documents cannot save its application settings or window history, it lists
the affected files in a **Save Settings** warning. Check folder permissions and
available disk space; changes to those settings may not survive closing the app.
## Common comparison choices
| Area | Examples of what it controls |
| --- | --- |
| Text | Case, spaces, tabs, quotation marks, character-level detail and move detection. |
| Fonts | Family, size, style, color and supported character effects. |
| Paragraphs | Alignment, direction, spacing, borders, shading, indents and tabs. |
| Document regions | Headers, footers, footnotes, endnotes and bookmarks. |
| Comments and fields | Comment changes and selected field-code families. |
| Objects | Supported images, OLE fingerprints, text boxes and frames. |
| Tables | Cell content, selected cell formatting and structural changes. |
If you turn an option off, a difference in that category may intentionally
disappear from the result. Review the scope before interpreting “no differences.”
## Images
- **Image Diff** replaces a changed picture with its visual difference image in
the redline, keeping the original picture's position and display size.
- **Combinational** keeps the original picture and adds the visual difference
picture beside it. Changed image content participates in the comparison.
- **Delete Images** removes pictures from the redline and suppresses image-only
revisions, including invisible picture markers.
## Tables
Use **Structured** table comparison for normal reviews. It identifies supported
table, row and column changes and merge/split operations. **Compatibility** is
the older mode for reproducing historical behavior.
Complex tables and repeated cell content can make alignment less certain.
Always check the surrounding rows and columns when a structural change matters.
## Fields and document properties
Fields can contain instructions as well as visible text. Choose the field
families relevant to your review. The result describes stored field instructions, not newly calculated Word
results. See [Privacy](/docs/privacy) for how the engine handles external content.
Some document-wide properties are reported as a change to the document rather
than as a precise word or paragraph location.
## Reuse a profile
Save a profile for a recurring review policy, such as a wording review or a
formatting review. Give it a name that explains its purpose. Agree on a shared
profile when several people need comparable results.
After changing comparison options, run the comparison again to produce a result
using the new scope. See [Review differences](/docs/documents/review).
## Conversion and session choices
Word or SDK conversion can affect formatting; see [conversion behavior](/docs/file-formats/#conversion-can-affect-results).
PDF inputs have a separate [OCR workflow](/docs/documents/pdf-ocr).
Builds offering overrides in **NewDiff** let you change options for one comparison
without changing the saved style. Verify the session settings before starting;
older installed builds may not expose these overrides.