The location varies by product type. Below is a breakdown by category.
On the ASUS Support Driver & Tools page, users often search by model name. However, different production batches of the same model (e.g., a ROG Strix G15) may have different Wi-Fi cards or Panel manufacturers. asus serial number
Most ASUS products have a white or silver sticker with a barcode where the serial number is listed after "SN" or "Serial Number". The location varies by product type