Most platforms (like Facebook or Reddit) do not allow you to upload .zip files directly to a post for security reasons. Instead, upload the file to a cloud service like Google Drive , Dropbox , or a simple sharing site like Wormhole or file.io . Once uploaded, copy the sharing link and paste it into your post.
If the file contains code or a game, platforms like GitHub or Itch.io allow you to upload zip files as "releases" or project files for users to download. Tips for a Successful Post How To Add / Attach A Zip File To A Website For Downloading File: Unsouled.zip ...
If you are "posting" this to a specific person, you can attach it directly to an email by clicking the attach (paperclip) icon in your email client and selecting the Unsouled.zip file from your computer. Most platforms (like Facebook or Reddit) do not