You can format entire rows or columns based on cell values using conditional formatting in Excel. Here's how:

1. Select the data range:

- Choose the rows or columns you want to format based on a specific cell value.

2. Apply Conditional Formatting:

- Go to the "Home" tab on the Excel ribbon.
- In the "Styles" group, click on "Conditional Formatting."
- A dropdown menu will appear with various formatting options.

3. "Use a formula to determine which cells to format" rule:

- Select this option from the dropdown menu. This allows you to define a rule based on a specific cell value.

4. Enter the formula:

- In the "Format values where this formula is true" field, enter a formula that checks the condition for formatting.
- Here are some examples:
- Format a row if a value in a specific column (e.g., column B) equals "Completed": `=B1="Completed"` (Replace B1 with the actual cell reference in your data)
- Format a column if a value in a specific row (e.g., row 2) contains the text "High": `=$A2="High"`
- You can use comparison operators like ">", "<", "<>" for greater than, less than, or not equal to conditions.

5. Set the formatting:

- Click the "Format" button.
- A formatting window will open, allowing you to choose font styles, fill colors, borders, etc., for the cells that meet your formula condition.

6. Apply the formatting:

- Once you've set the desired formatting, click "OK" on both the formatting window and the "New Formatting Rule" window.

Excel will now automatically apply the formatting to the entire row or column based on the value in the specified cell and the defined formula.

Tips:

- You can create multiple conditional formatting rules for the same data range to handle different formatting scenarios based on various conditions.
- Use absolute cell references with dollar signs ($) in your formula if you plan to copy the rule to other cells and want to maintain the reference to a specific cell.