You can use several methods to keep track of changes made to a document.

1. Make your changes to a copy of the document (stored in a different folder, or under a different name, or both), then use Writer to combine the two files and show the differences. Click Edit > Compare Document. This technique is particularly useful if you are the only person working on the document, as it avoids the increase in file size and complexity caused by the other methods.
2. Save versions that are stored as part of the original file. However, this method can cause problems with documents of non-trivial size or complexity, especially if you save a lot of versions. Avoid this method if you can.
3. Use Writer’s change marks (often called “redlines” or “revision marks”) to show where you have added or deleted material, or changed formatting. Later, you or another person can review and accept or reject each change. Click Edit > Changes > Record. Details are in the Writer Guide.

Not all changes are recorded. For example, changing a tab stop from align left to align right, and changes in formulas (equations) or linked graphics are not recorded.