You can use slash commands to import ppt presentations into your workspace.
To share and import ppt files:
- Open the channel or the member in your Slack workspace.
- Search and share the required presentation to the concerned channel or member using the attachment icon in the text area.

- Once the shared notification is received, you can upload it into your workspace.

- Once the presentation loads, you can click Open to view it in the Listing page.
Related link: