Wow, you’re right. All of Airtable’s forms — both form views and interface forms — are currently broken on mobile devices!
There is currently no ability to upload attachments or photos from mobile devices.
Be sure to report this as a bug to support@airtable.com.
Hopefully, Airtable will fix this very soon, but in the meantime, until Airtable fixes this problem, your best bet is to quickly rebuild all of your forms with Fillout’s advanced forms for Airtable, where uploads are still working properly on mobile.
Fillout also gives us 100+ advanced form features that Airtable doesn’t offer, such as updating Airtable records from a form, displaying Airtable lookup fields & rollup fields & formulas on a form, accepting payments on forms, having multi-page conditional forms, and much more.