You can make search operations in the application case insensitive by enabling case insensitive search for the required entity/column. This is achieved by adding the attribute CaseInsensitiveSearch in the required entity XML file.
To enable case insensitivity:
Include the shadow column attribute ShadowColumnName in the Entity XML and specify a name for the shadow column. If this is left blank, the system auto generates one. However, you must specify a shadow column name if you are indexing the shadow column.
A shadow column is then generated, which is linked to the original column that is marked as case insensitive.
For custom columns that have been extended, the case insensitive search works if the normal search works on those columns.