Install PHPMailer in Azure Web App

Pawel Partyka, as far as I know, Microsoft restricts using smtp on Azure and the best recomendation is to use one of the managed solutions offered by the platform such as send grid. Although if you run a subscription on production, you might find interesting following this doc: https://docs.microsoft.com/en-us/azure/virtual-network/troubleshoot-outbound-smtp-connectivity#recommended-method-of-sending-email

Concerning the application itself, i don't see you having any problems on deploying it.