User Defined Fields (UDFs) were designed to enable you to record extra pieces of information on a student profile that are not standard across all schools, or that don't fit into the other areas in Arbor.
Key pieces of information that are mandatory (such as for censuses) should already be located within Arbor's preset sections. For example, adding a second language would be added in the 'Language Abilities' Section of the Student Profile.
Adding the information into the correct area ensures the correct follow-up actions are triggered as well. For example, if the child's native language is not English then the student will get the EAL tag on the student record. If the second language was added as a UDF, this wouldn't make them EAL.
UDFs are therefore standalone pieces of information rather than linked to any area in Arbor, and sit within their own UDF section. It is not possible to separate UDFs and add them to different sections of Arbor.
If you use many UDFs at your school, you may wish to specifically name them so it is easier for users to find the details, such as noting which 'area' they are about.