Ideally you'd be using a Data Connectors integration to accomplish this. There are a lot of existing integrations, but if yours is not listed, you can still use a generic data connector.
The basic concept is that the user who has access to the Analytics UI creates a data connector integration. Once created, they are provided with a spreadsheet template and FTP location the data should be uploaded to. From there, you could upload that data to the FTP site so it can be processed for use in Adobe Analytics.
Those steps are quite simplified, and usually Data Connectors integrations involve a consultant to make sure things are done right. The Adobe Analytics user has an account manager they can contact to see if this is a route they want to explore with you.
See here for Data Connectors integration documentation: https://marketing.adobe.com/developer/documentation/genesis/c-overview-how-it-works