Unlock the Password Vault in the mobile app and choose Import passwords from its action menu. Choose Generic CSV, Google or Chrome, Bitwarden or 1Password, then the file. The file is read on your device and never uploaded. Review the items, including any that may already be in your vault, then import them. Each item is encrypted before it is saved. Delete the CSV file afterwards, because it holds your passwords in plain text.
Import passwords into the mobile Password Vault
The mobile Password Vault can import a CSV export from another password manager.