First, whether it is possible to integrate SmartPush Wordline or not, depends from both the level of integration you wish and the API that is provided by SmartPush.
Usually, these solutions allow SMTP connections, so for a simple fire-and-forget integration, no further steps are required.
But if you plan to use SmartPush's feedback features, you may need to write some Java code, either as a Function or as a JavaStep. Depending on the type of the available APIs (already mentioned above ...) you may be able to utilise already existing higher level functionality, like REST or SOAP connectors.
But I am currently not aware that there is an already existing integration for SmartPush Wordline into Pega.