E-mail or e-mail or E/email? I am finding a variety of content on the proper way to write this term.
Nowadays, ‘electronic mail’ is shortened to ‘email’
It's nearly always written as one word email, without hyphens, the compound noun has become solid for quite some time. But if the OP wants to write it as e-mail or E-mail it isn't wrong, just pick one spelling variant and be consistent.
From Historical Usage on Dictionary.com,
The lowercase form internet is regularly used in technology-related publications and in most informal writing such as social media posts, email, and text messages. And lowercase is increasingly being used in formal, edited writing such as newspapers.
The expression World Wide Web over the years has become truncated to the easier-to-say web . The term Hyperlink , though still in use, has been overtaken by its shortened version, link. An instant message is more often referred to simply as an IM. In most Internet contexts, the adjective electronic has been shortened to the prefix e- . So electronic mail has become email (originally e-mail ), and other popular compounds like e-learning , e-wallet , e-signature , and e-commerce have followed suit.