Hello, i setup my WHMC and registered one test hosting account. Now its waiting for payment. So in admin i setup "PayPal" gateway (no express, only paypal) and there i set my Premier paypal acocunt email. Ticked only checkbox: Force Subscriptions
And filled API details.

It is now saved and when i do on Invoices page as an Customer. I see my unpaid invoce, i select PayPal. There is orange paypal button


I click it and it redirects me to paypal payment page.
But there is no mentioning about SUBSCRIPTION.

I think it should be visible there?

Unless disabled in the PayPal gateway config, when a user views an invoice for a recurring product or service they will be shown a PayPal Subscribe button:
There are two conditions that must be met for the PayPal subscribe button to appear:

The invoice's Due Date must be in the future
The invoice must contain at least 1 recurring product (ie. domains and billable items on their own won't create subscriptions)

For more info on setting up a Paypal gateway please refer to