Login as the application implementation consultant
Go to Setup and Maintenance task "Manage Administrator Profile Values"
Enter the source mode profile code of "FND_ALLOW_MANUAL_METADATA_UPDATES" and do the search on the details page.
In the profile, value drop-down please select 'Yes' to enable the source view mode in FUSE+ UI.
I hope this blog post was helpful for you. If you have any questions or feedback, please leave a comment below.