Installing a link in to all product descriptions

Is there any way to add a link on the product description page automatically? I guess there may be a file that can be edited?

can anyone please help me :)

Whatever you're asking for isn't clear. What's "the link" for? What do you mean by "automatically"?

More importantly, maybe it would be appropriate if you explain the business logic behind whatever is making you think you need some sort of "automatic link" on certain pages?

I wish to put some text on each of my product descriptions as the bottom of the page which also contains a link to an external site.

I'm asking if there is a way to do this in one go by changing the product description code?... rather than adding the link to the 1000 or so products one at a time. eg I used to be able to change the pop up product image to cater for a banner below the image. Is there a similar method for the product description file?

In easy terms, I guess I'm asking what the product description file is called?

Are you asking to put the SAME text onto EVERY product page?
Or is it supposed to be uniquely different to each product?

The same text and link in each product. No unique ones. This is why I understand it should be possible with no real problems.

In that case, you could add your link code near the bottom of /includes/templates/your_template/templates/tpl_product_info_display.php.

I've had to do this on numerous occasions to mass products in a certain category. e.g., need to have a link to a page with details on what a specific attribute is and/or a link to a sizing chart.

I ended up using Easy Populate (Free langer modhole v1.2.2.5) to download all the products, open the EP file in a spreadsheet, paste in the hyperlink to each product description as needed, upload the EP file. It can be a hassle, but it's a solution that worked for me.

If the required text or link is the same for ALL products, then gjh42's answer is correct.

Perfect - thank you!!