Uploading HTML emails to my website directory

Hi, I need to be able to upload my html marketing emails onto our web directory as we are migrating from an external provider to internal emarketing system.

I would like to enable the ‘View in bowser’ hyperlink on our emails but in order to do that I need to create an online version of the email. Perhaps I am not looking in the right places but the ‘Upload’ on the front end Webflow is not allowing for html files just images, pdfs and css.

Can someone please advise on how do I get to the website directory to upload those htmls?
Apologies for a non scientific language