You don't have to "add" funds to your account. They get added as and when others make you payment.
If you still want to add funds, then you have to get hold of someone with a merchant paypal account who can use his account to receive funds with credit card and then transfer to you. All this will have charges.
But if you have a personal account, you can't accept payment thru credit cards, only thru other paypal accounts.
I have two paypal accounts (one personal and one merchant) both are verified.

But I hardly ever use personal

Kept it because there are no annual or recurring charges