Unfortunately, Airtable’s interfaces were only designed for internal team members, not external vendors.
It is only possible for your vendors to have writeable access to your interface if you pay for all of them to have Airtable accounts. Then they can log into your interface.
However, if you create a normal form view (not in an interface), anyone in the general public can have access to that form view. No Airtable account needed.
But it sounds like what you are looking for is a portal app.
The #1 best way of doing what you want to do would be to use an external portal tool, such as Noloco, Softr, JetAdmin, or Glide.
Noloco is probably the most powerful portal available for Airtable. I give a brief tutorial of Noloco on this episode of the BuiltOnAir podcast.
And I also presented a full one-hour webinar on Noloco called Building a Client Portal on Noloco powered by Airtable.
p.s. 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 consulting — ScottWorld