You can upload files to Teamup for quick access to documents, images, and other resources right on your calendar. It's not possible to edit attached documents directly from Teamup without having to download them and edit them locally. However, if you want to access and edit relevant documents quickly from Teamup, try this approach:
Store the files in the cloud where you can edit them. For example, your spreadsheet could be in Google Sheets. Or you could access documents from Dropbox, Google Drive, or OneDrive.
Then, insert the link to the file(s) into the corresponding Teamup event.
An event page with a link in a custom text field and a link in the event description.
You, or anyone on the team with calendar access, can quickly open the document, make the needed changes, and save. The link on the Teamup event will always point to the latest version of the file.