If you’re working in a View and try to filter a column, but don’t have the option, follow these instructions to fix. An example of this situation:
We need to make the field searchable. Navigate to Settings, then Customizations, then Customize the System:
Expand the Entity that your View was in, then select Fields:
Open the field that you need to edit, then change “Searchable” to Yes, then Save & Close:
Don’t forget to publish your customizations! The column in the view can now be filtered.