Edit email subscription confirmation page

Hi everyone,

Due to GDPR laws, everyone who subscribes to receive marketing emails from us has to double opt-in for them. When they opt in twice, this is the page that appears.

The template is from the POWER Theme and I would like to edit the text because it doesn’t fit the activity that would’ve just happened. How can i edit “Email Unscubscribe” text as well as as the text above “You have succesfully updated your email preferences”?

I’m sure it’s pretty simple but I have no html or css knowledge.

Thank you!!