Your Evernote account has a secret email address and any email message forwarded to this address is automatically archived as a new note in one of your Evernote notebooks. You can forward PDFs, travel receipts, audio clips, images and other important emails to this email address and they will be archived forever in your Evernote account.
You can send emails from Gmail to your Evernote account manually or you can use services like Zapier or IFTTT to automate the task of creating notes in Evernote from your Gmail mailbox. For instance, you can star a message in Gmail and it is sent to Evernote. Or can you apply the label Evernote to a message inside Gmail and IFTTT will forward the message with attachments to Evernote.
While it is easy to integrate Gmail and Evernote with the help of external services, a downside is that you would need to grant full access to your Gmail mailbox to a third party service. If you are not happy doing that, there's an alternate solution that uses Google Sheets and it can be implemented in less than a minute.
Let's see how: