If you want to deactivate your hosting while keeping your Hostinger user account and you have more than one website, you will need to remove your add-on domains first by following these steps: How to delete a website from a hosting account
Once you have only one website, go to Hosting → Manage, search for Deactivate Account on the sidebar and click on it:
Keep in mind that deactivating an account means that all files, databases, emails, and any configuration will be lost. In case you need backups before canceling hosting - be sure to download them beforehand. You can also backup your email messages using Webmail.
You will have the option to cancel your hosting right away or at the expiration date. Select your choice and click on Continue:
There read the warning, mark the checkbox, and click Cancel hosting:
That's it! Your hosting will be canceled, auto-renewal will be disabled and all data will be scheduled for deletion.
If you wish to revert this action and the hosting account isn't due for expiration yet, it is possible to reactivate it.