Final answer:
Theo should use Conditional Formatting to apply formatting to record data based on values in comparison with values in other fields. It is used to highlight patterns and trends in datasets by automatically changing the appearance of cells based on their data.
Step-by-step explanation:
If Theo wants to apply formatting to record data based on values in comparison with values in other fields, he should use Conditional Formatting. This feature allows users to automatically apply formatting such as font and background color changes to cells based on the data they contain. For example, if he wanted to highlight all cells with a value higher than 100, he could set a conditional formatting rule to do that. This is very useful in data analysis and visualization as it helps to easily identify patterns and trends within a dataset.