Need advice in choosing web app framework

I'm not really sure if this belongs here but:

My boss asked me to create a (mobile)web app which basically is a web form with the functionality to upload/send pictures and some input fields.

One of the input fields would be a select with data coming from a database.

When posting the web form, an email should be sent including the submitted data and pictures. So I would assume that a back-end needs to be created as well, possibly node.js or are there any other services that could provide this functionality?

An extra needed functionality would be multi language/localization support.

Also, it is preferred to be hosted on Azure.

I have an asp.net/SharePoint background but I have never had to create a full stack web app. I'm not really sure were to start when picking the framework to build it all (Angular, Polymer, MEAN stack,..)?

I have been following HTML5/CSS3/JS tutorials throughout last year but always theoretical, never anything practical. So I feel like I have a good theoretical background but lack the practical experience to start a new project.

Any good starting point/advice would be much appreciated.