How can we upload files (excel/word) via gallery in Fusion Field Service

Summary:

Hello,
We are using Fusion Field Service in our implementation.
Currently, we are using fusion attachments to send attachments from FFS to Maintenance Work Order.
These Fusion Attachments only allow us to upload a photo via the camera on mobile devices.
As per our use case, we would like to attach a file (excel/word) when we end an activity.
Currently, we are unable to do so.
Kindly help us in this matter.
Also, if I use OCI object storage instead of Fusion Attachments, will it help us upload attachment files via gallery ?
Any integration is required to send these attachments back to maintenance work order