For your domain to be properly connected to your hosting plan at Hostinger, the domain must be pointed to Hostinger nameservers.
Hostinger nameservers are as follows:
You can double-check this information in the Members Area → Hosting / Websites → Manage → Plan Details:
It is enough to set only the nameservers values if your domain provider does not require the IP addresses.
After updating nameservers, DNS propagation will start and go on for up to 24 hours; during this time, it's expected that your website won't work
Domain nameservers can only be updated on the domain provider's website, i.e. the place you purchased the domain from
For example, if you've bought a domain from Hostinger, the nameservers are updated via the Hostinger dashboard, and if you've bought a domain from Cloudflare, the nameservers are updated via the Cloudflare dashboard
If your domain provider doesn’t allow changing nameservers, you can point your domain to Hotstinger by creating an A record instead