Notes Section is non- editable in Create mode of form ,MS CRM v2015

Hi,

MS Dynamics CRM 2011 website has been upgraded to MS CRM 2015.

Notes section was editable in MS Dynamics CRM version 2011 instance but is non editable in 2015 instance.

Is this MS CRM  2015 out of box feature?

If yes, how to make notes section editable in form Create mode in 2015 instance?

Thanks!