Click Spaces , then select the files, and drag and drop them to any space in the spaces list. The message area opens automatically so you can confirm that you want to copy them into the space. Then, just type and send your message to share the files.
just type and send your message
Webex | Drag and Drop Files to the Spaces List
You can quickly share files to a space by dragging and dropping them directly to any space in the spaces list in the Webex app, such as a space with another person, a team space, meeting space, or a space in the search results, without opening the space first.