Create a new OneDrive document: In a new message, type /onedrive and select Create a document, Create a presentation, or Create a spreadsheet. You’ll be prompted to give the file a name, optionally add a message, and choose which channel or DM to post it in. The file will be created in your default OneDrive location.
Creating a new Excel spreadsheet from within Slack.
Howard Wen / Foundry
Share a document stored in OneDrive or SharePoint: In a new message in a Slack channel or DM, type the command /onedrive and select Add from OneDrive & SharePoint. From the panel that opens, you can browse and search your OneDrive and SharePoint to select the document that you want to share.
Share a document stored in OneDrive or SharePoint as a link: From the OneDrive or SharePoint web app, select the document that you want to share and create a publicly shared link to it. Then paste this link inside a new message in a channel or DM.