Can I offer clients more than one way to pay the same invoice?

Yes. Enable as many of the six rails as you like, and every one you've turned on shows up as its own pay button on the invoice in the client portal.

So a single invoice can offer, say, a card via Stripe, UPI via Razorpay, and PayPal side by side — the client picks whichever they prefer. Whichever they choose, the payment reconciles against that one invoice. Giving people their familiar method is often the difference between getting paid today and chasing them next week.