Hello,
I am no expert so if this is irrelevant I apologize.
Connect servers or external devices with Files on iPhone - Apple Support
"Connect to a computer or file server
- Tap at the top of the Browse screen.
- If you don’t see , tap Browse again.
- Tap Connect to Server.
- Enter a local hostname or a network address, then tap Connect.
- Tip: After you connect to a computer or file server, it appears in the Recent Servers list on the Connect to Server screen. To connect to a recent server, tap its name.
- Select how you want to connect:
- Guest: You can connect as a Guest user if the shared computer permits guest access.
- Registered User: If you select Registered User, enter your user name and password.
- Tap Next, then select the server volume or shared folder in the Browse screen (under Shared).
To disconnect from the file server, tap next to the server in the Browse screen.
For information on how to set up your Mac to share files, see Set up file sharing on Mac in the macOS User Guide."
I hope this is helpful.