You don't necessarily need a screenshot, a copy of the webpage the user saw would IMO be sufficient.

You need to be able to show the user agreed and what they agreed to exactly. A screenshot might do that but might also not be sufficient (if there is more text elsewhere on the signup process related to privacy)

For all downvoters:

https://www.mailjet.com/gdpr/consent/

Scroll to: How do I store consent under GDPR?

The record of the IP address, location and time at which someone submitted a consent form is insufficient without a screen capture of the form itself.

You welcome!

The specific recital is here: https://gdpr-info.eu/recitals/no-42/

A screen capture is the easiest way to achieve compliance but the regulation leaves open other methods as long as you can show that someone gave consent and to what exactly. (IMO you could also store the HTML of the webpage they viewed at the time)

That’s the weirdest thing. What do the law mean with a “screenshot of the form”

There is nothing about a screenshot in the law.

The law says you have to be able to prove the user ticked the box and provide an audit trail for it, IIRC some recitals mentioning that you should be able to reproduce the exact agreements the user made (ie, either in text or as a screenshot) so that you can later show the user and any regulatory body that asks what they agreed on.