How delete a default value in custom fields

Summary:

Content (required):

Hello experts,

is there a way to delete default values in drop-down fields?

For example in Termination quick action there is Voluntary Termination as default value. Is there a way to delete default values?

If so, how can we do it?

Kind Regards,

Valerio

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):