Great question — answering as the UphillTech team:
This really depends on what data you are trying to collect. If you are just trying to collect standard customer info you can create your own form in .liquid and have a webhook forward the info to zapier or create a private app key/pwd and use the Shopify api to pull information. If you want more arbitrary information you can create or use an app that allows you to create a form and then process that form's responses. I have a forms app in development that allows you to create a form and use an api to pull data from form submissions or have the form response sent as a JSON email body. ( https://knightsofthenet.herokuapp.com/questionnaire/ ) Some of the competition will just email the...
Full answer by bknights: https://stackoverflow.stackexchange.com/a/47480207 (CC BY-SA 3.0).
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