Admin users do have the ability to create custom fields that appear in CRM(Companies, Contacts, Candidates, Job Orders):

To create a new CDF(Company Defined Field) you can click on the 'Add' button. After clicking 'Add' you will be prompted with the following window:

You can determine which CRM screen for the field to display as well as if it's required or not. You can then name the field and select the field type(Text, Dropdown, Radio, etc).

If you select a field type that will display multiple values you must enter those values and mark one as a default.

They will be displayed within the CRM record similar to the below:

You also have the ability to filter by these CDFs using Akkusearch. Please note that it will take a few minutes for the filters to index and appear after creating a new CDF: