Hello
I’m using Hivexpert theme
I add a premium service to be paid from the customer
I installed the Woocommerce and HivePress Paid Listings Plugin
everything works fine except the payment method
We are sorry but this issue is not specific to HivePress. The theme itself and the plugin that powers it (HivePress) doesn’t implement any payment gateways, it’s integrated with WooCommerce for this purpose. So HivePress basically adds multi-vendor features to WooCommerce, while all the purchases are handled by WooCommerce checkout. If you have issues with setting up PayPal in WooCommerce/Settings/Payments section please refer to their docs Supercharge your WooCommerce store with PayPal
If PayPal was correctly set up on your website then please send more details that may help to detect or reproduce this issue (e.g. a link to your site, screenshots, a list of installed plugins, or the error message you get).