Sharepoint – Document Managment – Why can’t I see the Document option under Related tab for my entity ?

The answer is coz

Step # 01 You haven’t enabled server based sharepoint integration for your environment

Open Power Platform Admin Center and navigate to your environment >> Settings >> Integration >> Document Management settings

Follow the wizard, select Online and enter the default site url.
CRM URL : https://***.crm5.dynamics.com

Default Site URL: https://***.sharepoint.com

The default site remains the same irrespective of the environment.

Step # 02 You haven’t enabled the entity for Sharepoint Document Management

Step # 03 Configure Document Management Settings

If you have enabled your entity for sharepoint, it will be selected already in the list :

Enter the same sharepoint default site url and proceed further.

Select Based on Entity

Once done, it will show the status Succeeded and now you can see the Documents option for your custom entity.