Sharepoint expert needed for project

I need a solution for this: I need to interact with external users in my sharepoint site.
I need a page/web part where external users can input the following: A number/text/confirm button or add a digital signature (sign contracts), I want to insert these data to a sharepoint list.
Is that possible? We use Powerapps today, but I understand that we can’t share powerapps with external`?
With external users, I mean pepole outside my organization (and they don’t have licence)
I understood that it is possible in sharepoint, if we share the page with anyone with the link?
Possible with SPFX or similar solution? Please advise!