If you have a Domain name registration, your information is shown online via public WHOIS listings. Each and every Domain owner must provide and verify his Contact information, due to ICANN regulations.
However, your Domains WHOIS information can be hidden with the help of a domain privacy service.
Hostinger offers this service too and you can purchase it from your Domains management section that can be accessed by clicking on Domains in your Hostinger profile and selecting your owned Domain. Look for a title that says "Would you like to keep this information private?". If you do, click "Order"
Once the privacy setting is ON, your data will be hidden from public WHOIS listings, as soon as they update. Please note that some WHOIS listings can take some time to update their information on Domains, so your private information may not be hidden instantly from all WHOIS listings.
Domain privacy is NOT supported for the following TLDs due to registry regulations: .asia, .ca, .de, .es, .eu, .in, .nl, .pro, .ru, .uk, .be, .br, .ch, .cz, .fi, .gr, .li, .nu, .pl, .pm, .ru, .se, .tf, .us, .wf, .yt.