Include subscriber ID to the URL

Hi @saksmoto ,

You could try use one of the survey platforms we do integrate with to have the data sync over to Klaviyo. Or utilize Klaviyo's API and a site like Survey Monkey.
You can hyperlink a link to the survey in a button to direct the customer to the survey. More information can be found here: How to Use Links to Collect Information About Your Recipients. Once you integrate a survey site with Klaviyo, you can sync appropriate information to Klaviyo which can be used to analyze the data. 

If you are looking to send out an email that will allow your customers to update an existing property, you can use buttons within the email to do this rather than using a form.
https://help.klaviyo.com/hc/en-us/articles/115005255248-Use-Buttons-in-an-Email-to-Collect-Information-About-Your-Recipients

What you will do is add this tag as the URL within the button:

{% update_property_link 'profile_property' 'property_value' 'redirect_link' %}

Then you will assign the existing property and add the new value for when the customer clicks the button. Then to finish the setup, add a redirect link. When someone clicks the button, their profile property will be updated based on the button they click.