Here's how to format PivotTables with custom number formats in Excel:

1. Select the desired field:

- Click anywhere within your PivotTable to activate the PivotTable Analyze tab.
- In the "Active Field" group, locate the field you want to format (e.g., Sales, Quantity).

2. Access Field Settings:

There are two ways to access Field Settings:

- Method 1: Click the "Field Settings" button within the "Active Field" group.
- Method 2: Right-click on the field you want to format and choose "Number Format" from the context menu.

3. Apply Custom Formatting:

- The "Field Settings" dialog box will appear.
- At the bottom, click the button labeled "Number Format".
- This opens the familiar "Format Cells" dialog box.

4. Choose the desired format:

- In the "Format Cells" window, explore the various number format categories (e.g., Number, Currency, Accounting, etc.).
- Select the specific format that best suits your data (e.g., comma separators for thousands, percentage signs, decimal places).
- You can also create a custom format code by entering it directly in the "Type" box.

5. Apply and Close:

- Once you've chosen your desired format, click "OK" on both the "Format Cells" and "Field Settings" dialog boxes.

Additional Tips:

- You can format all value fields in your PivotTable at once by selecting the entire PivotTable before accessing "Field Settings."
- Remember that formatting changes applied directly to PivotTable values might not be permanent. If you refresh or pivot the table, the formatting might revert. For a more permanent solution, consider formatting the source data before creating the PivotTable.