Hi ThangaKumar,
You're absolutely right, you may choose the 1:N Relationship ("Only Related Records") data sources to be displayed within your grid, which would display every Opportunity related to the Contact record you're currently on.
However, if I understand you correctly, you'd like to add a subgrid to the Contact form that contains information about every Opportunity in CRM (so, no filters). If so, then simply add the Subgrid and use an "All Opportunities" View. You can select
"All Record Types" under the data source options.
If you simply want a grid with all the Opportunities, I'd suggest creating a View in the Opportunity Entity with no filters, and then either use it in the Contact Form, or on the Opportunity entity itself.
Hope this was helpful,
Thank you,
