Can't get out of read-only for my new Passport

It’s in APFS format.
It’s backing up in Time Machine fine.
But no folders or files are able to be added.
‘Get Info’ shows “You can only read” in Sharing & Permissions, but there is no lock icon present to change the ignore-ownership setting.

Help please.

I request you to test the drive health status through WD Drive Utilities and share the test results with us.

Title: How to install WD Drive Utilities( For both Windows and MAC)
Link: How to install WD Security & WD Drive Utilities