You can customize your subscribe and unsubscribe forms and confirmation messages by using the same 'editor' that you use when creating emails. You will be able to insert links and images and format text.
Subscribe Customization: You can customize the content that appears above your subscribe form and choose which form fields display as optional or required. You can also customize the subscription confirmation message that the subscriber sees when they click the link in the confirmation email.
Unsubscribe Customization: You can customize the content that appears above your unsubscribe form and the unsubscribe confirmation message.
If you have a 'custom interface' as part of your membership, the subscribe/unsubscribe process will contain your custom interface so your subscribers can easily identify you by your branding.
If you are a Multi User Administrator, your customized forms and confirmation messages will be shared when you add a new user. Your users can further customize the forms and messages if needed.