Have a dedicated form for your list which is used solely for GDPR consent.
To get consent to keep sending to your European Union contacts you will need to use a consent web form. These steps will show you how it can easily be done.
Click 'Lists and Forms' on the left hand side and double click on the list you're working with.
Click on the 'Preferences' web form tab, then click the 'copy' button on the right :
Name the form 'Consent' (or something similar) and click the 'copy' button.
Now that you have your copied form, the last step is to delete the 'preferences' component.
Style your new consent form as you like (for example, double click on the form title and change
Your consent form is now ready!
You can link to this consent form by following the steps in this article.