I need to filter excel eliminate some characters and save the file in a sharepoint address
Do you use Office 365?
If so, install the package UiPath.MicrosoftOffice365 and use the Office 365 Scope. If enabled in Azure you can directly interact with SharePoint.
what activity do i use
Everything O365 interaction must happen inside the O365 Scope activity, because that creates a session with the azure server.
Inside the Scope sequence you can use the files activities to work with OneDrive and Sharepoint.
Make sure Azure is configured correctly. there is lots of information online.