After an email has been sent you can see who has not opened it and decide to retarget them excluding everyone who did open the original email.
First, in the analytics view click on the recipients tab.
Click on the "All recipients" drop down menu and select "Unopened"
Once you have the list of unopens showing you can then click on the 3 dot menu bar and select "Create list from" option.
A menu box will appear and prompt you to then create and name the list. Create the list and you've now created a list that you can specifically target for a resend!
Once you've successfully created and named the list you can now go back to that same email to resend to all unopeners or create a new email for them specifically!
NOTE: When GDPR mode is enabled, all open tracking is anonymized to protect your subscribers’ privacy. This means we don’t know which specific contacts opened your email, so features like targeting unopeners aren’t available. While that can feel limiting, it’s also what keeps your account fully compliant with GDPR requirements and ensures your audience’s data is handled with the highest level of care.