Delete and remove custom fields eg:- payment types.
The steps to delete or remove any custom field are as follows :-
Click on the setup menu and choose custom fields.
Select desired field you want to remove.

And choose the field by clicking on check box.
click on the action drop down list and choose remove selected items option.

NOTE :-
You can also delete the other custom fields by using the same method.
Click on the setup menu and choose custom fields.
Select desired field you want to remove.

And choose the field by clicking on check box.
click on the action drop down list and choose remove selected items option.

NOTE :-
You can also delete the other custom fields by using the same method.
Updated on: 02/03/2020
Thank you!