In order to change the font size of the product line in the POS receipt, you can use CSS to target the specific elements in the template and adjust their font-size property.

You can do this by adding a custom CSS file to your POS module, and then linking to it in your pos.xml file using the link element.

Here is an example of what that might look like:

Copy code<link rel="stylesheet" href="/module_name/static/src/css/pos.css"/>

And in the css file, you can target the elements you want to adjust the font-size by their classname or id

Copy code.pos-product-line {
    font-size: 14px;
}

You can also use t-style tag in your template to add the css on the fly

Copy codet-name="OrderReceipt" t-inherit="point_of_sale.OrderReceipt" t-inherit-mode="extension" owl="1">
    t-style="{'font-size':'14px'}">
        expr="//div[@class='pos-product-line']" position="attributes">
            name="style" />
        
    

It's important to note that this will change the font size of all product lines in the receipt, if you want to target a specific product line you need to use a more specific css selector