Household contents insurance, at times, can get a little bit confusing. To answer the question of who does it cover, we first need to ask the question what does it cover, (I’ll keep it short, I promise).
Household contents insurance covers the contents of your household. These are the things that, if you turned your apartment upside down, would fall out, like furniture, electronics, books, jewellery etc. The contents are covered against specific insured events such as fire, robbery, burglary, water damage, storm, and hail.
So, now that we’ve established what it covers, how does that relate to the original question, you might ask?
In essence, this policy protects the contents of your household - your belongings. Therefore everybody* living in your household’s stuff is covered. Just make sure that the insured sum that you select also includes the costs of replacing everybody’s belongings in the case of an insured event. You don’t need to make any changes in the policy to have their belongings covered.
What does it cover? - your belongings in the apartment, including your flatmate’s pioneer DJ set and your boyfriend’s Wassily bauhaus chair, as well as your landlord’s Persian rug.
Who does it cover? - everybody in the household.
*It's currently not possible to cover just your own belongings if you live in a shared apartment with this policy.