Administrator can add activities subview for a Custom Object using Extension Generator
Administrator can add task and appointment subview for a Custom Object using Extension Generator.

Task
This is a no code approach and administrator can add these subviews using Extension Generator
Steps to Enable
Leverage Application Composer to expose and adjust page layout and attributes. To learn more about extending your application using Application Composer, visit Oracle Help Center > your apps service area of interest > Books > Configuration and Extension.
Navigate to Extension Generator from Application composer, select required object Object and configure -> Subview and Select Activity.

Configure Subview