Go to Settings and then Custom Field Settings

Custom Fields are currently available for Lead Module, Client Module and Product Module

Step 1:
You can enable or disable the field in the module from here based on your requirement

Step 2:
You can make the field mandatory if required

Step 3:
If you need to display the field in the List All or Index Page of the particular module, you can do that from here

Step 4:
If you want to restrict your employees from editing a particular field, this option will be helpful.

Step 5:
You can add a new field which is not available in the module from here

Step 6:
You can select the type of field to be added either as text box, text area, dropdown or date picker. If you select dropdown, you need to enter the options seperated by comma(,) in the below field

Step 7:
You can select the new field column width from here. 1/1 is the full width, 1/2 is half of the screen width, 1/3 is one third of screen width and 1/4 is one fourth of the screen width

Step 8:
The newly added field will be displayed at the bottom of the default fields.

Step 9:
You can edit and modify these custom fields at any point in time based on your requirement

Step 10:
Option is provided to delete the field added as well.

Step 11:
After making necessary changes, click on the update button to make the changes live.