Question about IFrame and Security

[Rod]

I want to take advantage of some functions in appsheet rather than using another third party.
I want to place an Iframe form on a site that is just a form and reopens to a form, it doesn’t show anything other than the form. I’m collecting user info, i.e. email, phone, address. Doesn’t display the menu upper left or search, just the form.
Can I do this without any security issues and or without additional fees?
Thanks!