If Wix don’t already allow Fawry Pay then you can look at requesting it.
https://support.wix.com/en/article/requesting-additional-payment-providers
Otherwise, you can contact Fawry Pay and see if they have their own API that you can try to connect your site to.
https://docs.checkout.com/docs/fawry
https://www.wix.com/corvid/reference/wix-http-functions.html
https://support.wix.com/en/article/corvid-exposing-a-site-api-with-http-functions
https://www.wix.com/corvid/reference/wix-fetch.html
https://support.wix.com/en/article/corvid-accessing-third-party-services-with-the-fetch-api
You can see examples for using Stripe that you could see if it could work with Fawry as well.
https://www.wix.com/corvid/forum/corvid-tips-and-updates/example-stripe-payment-processing
Also, for exposing your site.
https://www.wix.com/corvid/forum/corvid-tips-and-updates/example-myapi-and-myapiclient