Impressum is a german word and it means mentioning the legally important information about your business. To make it simple, its a mix of your ‘about us’ page and ‘terms’ page 🙂
If you want to update Impressum section, you can probably put basic details like company full name, website link, contactable phone numbers and email ID, location, details of Directors etc.
Or you can consult with a legal team of yours.