Yes! You can use your purchased services at Hostinger with any domain that you have already registered. To do so, you can consider the following options:
You can point your domain to Hostinger by changing the nameservers while keeping the domain registration management (such as contact details and domain renewals) on your current provider
Alternatively, you can transfer your domain to Hostinger and have all your services in one place!
NOTE:
Some TLDs may not be available for transfer. In that case, you can still use your domain at Hostinger by pointing it to our servers. After you specify the new DNS records, propagation will start, which can take up to 24 hours to complete
Additional resources: