Elias here with Shopify Support. Thank you for this inquiry.
It is possible to set up your online shop with PayPal as a standalone payment gateway. Depending on the customer’s account or location, PayPal may offer ‘Guest payments’ so you can consider disabling this in your PayPal settings if you don’t want to accept other cards.
By default, Shopify Payments could be enabled for your store so you can disable this payment method and only have PayPal activated. That said, using Shopify Payments allows Shopify to waive an additional fee for third-party gateways so disabling that will subject your store to this fee. This fee varies, depending on the subscription plan you select for your store, feel free to take a look at our plans and features page.
We don’t have a guide for disabling Shopify Payments; however, you should see a deactivate button when you manage the gateway. Our ‘Set up Shopify Payments’ guide will take you to the right place, under ‘Settings > Payment Providers’ from your admin. Here’s a couple screenshots of what it looks like:
There are benefits to using Shopify Payments with your store, as it can be used with PayPal, allowing your customer’s more options to pay for their order. Shopify Payments does have limitations with certain types of business or products, you can find this information listed in the Terms of Service.
Since having more payment options for your customers will usually be beneficial to conversions/sales, is there a specific reason you only want to use PayPal?