This task requires the System Administrator or System Customizer security role A defined set of privileges. The security role assigned to a user determines which tasks the user can perform and which parts of the user interface the user can view. All users must be assigned at least one security role in order to access the system. or equivalent permissions. Customization tasks can be performed only while you are online. More information: Customization Permissions
If you have custom code that depends on certain fields being present in Microsoft Dynamics CRM Online, set these fields up as dependencies so that the fields cannot inadvertently be deleted from the form.
In the Navigation Pane, click Settings, click Customization, and then click Customize Entities.
Open the entity that contains the form that has the attributes your external code refers to, and then click Forms and Views.
Click Form, then on the Actions toolbar, click More Actions, and then click Edit.
In the Common Tasks area, click Form Properties.
On the Non-Event Dependancies tab, select the fields you want to make dependent, and click the Add Selected Records button to move them to the Dependent fields list.
Click OK to close the Form Properties dialog box.
Click Save and Close to close the form.
Click Save and Close to close the entity.
When your customizations are complete, publish your customizations:
To publish customizations for the entity you are currently editing, on the Actions menu, click Publish.
To publish customizations for all entities at once, open the Customize Entities list. On the More Actions menu, click Publish All Customizations.
To publish customizations for specific entities, open the Customize Entities list and select the entities you want to publish. On the Actions toolbar, click Publish.