What does this mean?

[banking]

Posting for traffic due to time of night !

Ordered a laptop from John Lewis which is now faulty. Contacted the manufacturer who asked for proof of purchase for warranty. Specifically:

For digital receipts, please provide the order invoice. We do not accept packing slips, email confirmation, or order history

I’m not great with computers, what exactly is my JL order invoice if none of the above counts? Do I access it from my account?

Did you buy online? If so, it'll probably be attached to the email you got then.

It means the email/invoice you got that actually names the product and cost, that it was paid and has your name on it etc.

Not just an email that says 'thanks for your purchase', a screenshot of your order history online or a slip that came with the computer that just says '1 laptop delivered'.

Thank you both. I feel really silly now!

Yes, online order. They attached a VAT receipt by email when the order was dispatched - is that the same as an invoice? Hoping it will suffice as it has all the details mentioned by @imsofuckingtired (great name btw !)

You might be able to contact John Lewis and ask for one. If you ordered online they will have a record of it in their systems.
Also, When I’ve ordered from John Lewis you sometimes get a guarantee in an email

It's an attachment they sent you in an email when you ordered. You need to send them that and not the email itself.