mobile app development

Greetings, I would like to add a custom payment gateway to my ionic 5 app for android and ios. The app backend is Opencart, the payment gateway (Pesapal ([login to view URL])) has already been added and working in the website. The link provided has all the API information plus examples. When Pesapal Gateway is selected it loads an iframe for the user to fill payment information. (see attached images, Website 1 and website [login to view URL]). In the app, payment method does show app but ionic requires customization so as to be able to load the iframe and make payment. (see image App 1 and App [login to view URL]). You can either load an iframe or add an additional page to redirect to ([login to view URL], see documentation) and return to the app to complete the payment. This should work for both Android and iOS app.