Yes, you can enable both global online payment processors.
To enable PayPal, see this FAQ:
How do I use PayPal and display Add to Cart buttons?
To enable Stripe, see this FAQ:
How to Use Stripe for Processing Payments
If both ecommerce payment options are enabled, when a buyer checks out, they will have the option to pay with a credit card (which will be processed via Stripe) or checkout using PayPal.
This is what the cart checkout screen will look like with both options enabled