Form submission resulting in email doesn’t include attachments

Hi all, I need some help with a bit of code I’ve written - and I am no coder by any means! This is me following blog posts etc.

I have a contact page on my website, which consists of several fields and a Submit button. Upon submitting the form, I receive an email with all the submitted details.

However, one field I have on the form is an ‘upload attachment’ field (for which you can see I added using the code below), and anything uploaded here does not come into the email as an attachment / image.

Can anyone help me understand what I need to do to ensure the email I get upon form submissions always contains the attachments uploaded by the customer on this page of my website?

Submit an image of your custom design, if you have one