I was actually in the middle of typing up all the same stuff that @kuovonne said above, so I will just trim down my comments to just the bare necessities now:
1. Airtable forms never allow you to view any information in a record, whether it is an attachment, text, or any other data. Airtable forms are simply blank forms that people can fill out to create brand new records in Airtable.
2. Your #1 best bet, as Kuovonne said, is to share a view. That is actually your ONLY option that will work within Airtable. There are no other options that will work with Airtable on its own.
3. Otherwise, you will need to use other services. Kuovonne lists a bunch of portals on her page that she linked to above.
4. In my personal opinion, the #1 best portal for your use-case scenario is to use Fillout's advanced forms for Airtable, because it is 100% free, it lets you view & update Airtable records from a form, and it will give you a unique URL link for each record. Fillout also allows you to show the values of any of your Airtable fields on your form itself, which is specifically what you requested above. You can show attachment fields, lookup fields, rollup fields, and you can even calculate formulas live on your form as well. You will currently need to use some workarounds to allow people to view/download an attachment field without giving them the ability to edit/upload/delete attachments, but chat with their support team and they will talk you through the process of doing it. (Fillout is also bringing read-only attachment fields in the near future, so workarounds won't be necessary in the future.)
Fillout is 100% free, and it offers hundreds of features that Airtable’s native forms don’t offer, including the ability to update Airtable records using a form, create custom PDF files from a form submission, accept payments on forms, pre-fetch dynamic data from an Airtable record, customize the style and branding of your form, customize a theme for your form, display Airtable lookup fields on forms, create new linked records on a form, add a login page to your form, perform math or other live calculations on your forms, collect signatures on a form, create multi-page forms with conditional paths, connect a single form to dozens of external apps simultaneously, add CAPTCHAs to your form, and much more.
I show how to use a few of the advanced features of Fillout on these 2 Airtable podcast episodes:
5. Alternatively, you don't even need to give people the ability to download the file directly from the Fillout form. You can just put your attachments in a cloud storage space like Google Drive, and just give people a clickable link on your Fillout form to click on.
If you want to automate the process of getting Airtable attachments to Google Drive and having a unique URL for each attachment, you would want to automate this process using Make. I talk about how to work with attachment fields and Make in this Airtable podcast episode: https://youtu.be/sKPyG0HZCYY?list=PLqssva4liHRwHhQIpTXekG8WObEoyC2F1
Hope this helps!
If you have a budget for your project and you’d like to hire an expert Airtable consultant to help you with any of this, please feel free to contact me through my website: Airtable consultant — ScottWorld