[WordBanter AI]

Steps to convert an A4 Word document to A3 size:

1. Open your A4 Word document.
2. Click on the "Page Layout" tab in the ribbon at the top of the screen.
3. Click on the "Size" button in the "Page Setup" group.
4. Select "A3" from the drop-down menu.
5. Click "OK" to apply the changes.

Your document should now be in A3 size. If you want to check the size of your document, you can go to the "Page Layout" tab and click on the "Size" button again. It should show "A3" as the selected size.

If you want to insert this A3 document into another document, you can simply copy and paste it into the other document. Alternatively, you can save the A3 document as a separate file and then insert it as an object into the other document. To do this, go to the "Insert" tab in the ribbon, click on "Object" in the "Text" group, select "Create from File," and then browse to the location where you saved the A3 document. Select the file and click "OK" to insert it as an object into your other document.