re: I want to build an Enquiry form that will have prefilled information and prefilled options based off the logged in user. e.g. they may have multiple delivery locations

Hmm, prefills will require user to click on a link that includes the prefill data I'm afraid: https://support.airtable.com/docs/prefilling-a-form-via-encoded-url

Maybe check out Fillout.com? Seems like they let you prefill stuff dynamically, but I'm not sure how that would work with the login stuff you mentioned: https://www.fillout.com/help/prefill-fields

For the multiple delivery locations thing specifically, you could do that with Interface forms I believe, you'd just need to assign an email to each location.  In your form you'd then have a linked field to the "Locations" table and have a filter on the email field for "Current User":

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re: I also want to have an option to create more options for adding products (as per below)

This is adding new records to the "Products" table I presume?  If so, I'd suggest trying Fillout.com as Airtable forms don't allow for linked record creation at this time.  A workaround people use sometimes is they provide a link to another form for users to create records there, then come back to the original record

@FPX 

You would typically want to use Fillout’s advanced forms for Airtable for this.

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, 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:

• Using Fillout to create an eSignature approval process with PDF file creation.
• Using Fillout to create an order entry form with line items.

Hope this helps! If you’d like to hire the best Airtable consultant to help you with anything Airtable-related, please feel free to contact me through my website: Airtable consultant — ScottWorld

Thanks mate. 

The products part is for buyers to submit an enquiry per line item (product) on quantity and price. 

I will eventually want to have this where enquires get sent to all suppliers on the marketplace (currently just me as the supplier).

Thanks