To create a custom field for any module you should have the correct permissions:
Step 1: Select Settings from the top info bar.
Step 2: Select Custom Field from the list.
Step 3: Select the module for which you are willing to add the custom field.
Step 4: Select Add field
A form will appear, as shown in the image below.
Step 4: Select the Module (Client, Partner, or Product) on which you want to add the field.
Step 5 – Name the section of your Custom field.
Step 6 – Give the Custom Field Name.
Step 7 – Select the Field Type (Text/Date/Number/Dropdown).
Step 8 – Here, you have two options. Check on Make this field Mandatory to add a Mandatory field and Check on Show this field on list view to view the field on related module’s table head.
If you select the Dropdown option, you can also select Allow Multiple Dropdown Selections so that multiple options from the dropdown can be selected.