You can make Excel highlight or style cells dynamically when checkboxes are checked or unchecked by linking each checkbox to a cell and basing a conditional formatting rule on that linked value.

Method: Using Linked Cells for Conditional Formatting

1. Go to the Developer tab, click Insert, and choose Form Controls > Checkbox.

2. Click on the cell where you want the checkbox to appear.

3. Right‑click the checkbox and select Format Control.

4. In Cell link, select the cell to store the checkbox state (e.g., C2) and click OK.

5. Select the range you want to format (e.g., A2:C11).

6. Go to Home > Conditional Formatting > New Rule.

7. Choose Use a formula to determine which cells to format.

8. Enter the formula =$C2=TRUE.

9. Click Format, choose a fill color (e.g., green), and click OK twice.

10. Check a box to see the corresponding row highlight automatically.

Method: Strikethrough Completed Tasks

1. Complete steps 1–4 above to insert and link checkboxes.

2. Select the task name cells you want to format.

3. Go to Home > Conditional Formatting > New Rule.

4. Choose Use a formula to determine which cells to format and enter the linked cell reference (e.g., =$B2=TRUE).

5. Click Format, go to the Font tab, and check Strikethrough.

6. Click OK twice to apply.