External User access to Appian application

Hi Community,

I have a use case where an external user has to be access Appian application to submit the requested details and attach necessary documents. For this, I can think of 2 possible approaches

1. Design a login workflow to provide access and using java servlet, capture the details. This definitely requires some effort and a challenge w.r.t user licenses if they are in huge number. Also, for the login workflow, can we configure an option to forgot security question?

2. Provide a standard template to enter the details and send the same to the respective SPOC (manually though email) to enter the details on their behalf. I know this approach will not cater for complete automation. To make it automated, does Appian has the capability to read incoming email along with its attachments when replied to the email triggered from Appian.

I'm looking for some pros/cons with above approaches and also other approach if any would be greatly appreciated.

Thanks.