CRM Forms already have a button to quickly send an email. The “Follow up” button allows you to quickly create activities, however it does not show up the entire activity form.
If you instead wanted a way to create a task or some other activity and want the activity form to show-up without navigating to the Activities pane and click on New and select the appropriate entity, here is the code that will help
- Send Email: locAddActTo(4202); // where 4202 = objecttypecode
- Create Task: locAddActTo(4212)
The entire list of ObjectTypeCode for all entities in CRM can be found in the SDK