The Solid Platform support includes attachments on all the resources. While adding an attachment, pass the resource id to which the attachment belongs. In response, you will receive a public URL, which is available for 5 minutes that you need to push the attachment to (supports standard mime types). 
{
  "id": "att_a8d2b191fa0e960d8e49a4bfd320e07b",
  "reference_id": "ctp_8e5541c8a9e50c3af3b0daacf9175130",
  "label": "formation",
  "url": "http://bucket.s3-website-us-east-1.amazonaws.com",
  "created_at": "2024-04-04T11:06:00Z"
}
API reference to add, retrieve, list and delete attachments are here.
You can add multiple attachments to a resource.