You can use this feature to auto-populate form values based on URL parameters.

To enable this, open the Settings panel when editing your form, and go to the Others tab, and check the option Pre-fill fields from URL attributes.

Pre-fill fields from URL attributes
Pre-fill fields from URL attributes

Our form is now ready to fetch values from the URL. This can be done via field labels or field values.

via field ID
via field label

If you have enabled Alternate Labels under Settings -> Others you can also populate fields via Alt Labels.

Some fields accept multiple options - like the checkbox field and the dropdown field. You can pass multiple values in this manner:[]=India&field32[]=Canada