There are two main requirements in order to pay with PayPal on Hostinger:
The Hostinger brand (Hostinger.com, Hostinger.co.uk, etc.) where your account is located has PayPal enabled. You can verify it here: What are the Available Payment Methods at Hostinger?
You have a debit or credit card connected to your PayPal account
After meeting these requirements, follow these steps to pay with PayPal: