Hello,

Try to create a variable product or simple product and add the regular price or sale price. In the product edit page, locate the “Product Data” section. Under the “General” tab, you’ll find the “Regular Price” field. Enter the regular price for the product in this field.

Select a variable product For each variation, you will see fields for Regular Price and Sale Price. Enter the appropriate prices for each variation.

For more details check this:
https://woocommerce.com/document/variable-product/

Best Regards.