Hi @121premkumar I've attached a Fusion file for you to review how I modeled this part. If you step through the history to review the sketches and features I have created, I think you will be able to easily follow how I created this model.
The tricky part that you are probably running into is that when you draw the sketch of the square on the front angled face, when you extrude that sketch, your extrusion ends up perpendicular to the face (normal to) instead of going in the direction you want. The good news is that this is pretty easy to deal with.
Here you can see I created the sketch and drew my square on the angled face of the part and added the dimensions. 
Finish that sketch, and then create a new sketch on the back face of the part as shown in this image.

Once you are in the active sketch on the back face of the part, from the create menu choose Project/Include and then choose Project.

You can then carefully click on each of the 4 lines that represent the square you drew on the angled face. That will project those entities onto the active sketch plane. As your mouse is moved over those lines, the edge will change to a magenta/purple color. When you see that happen click to project that entity into your active sketch. Continue this for the other 3 lines until you have projected all four edges.

Once you have all 4 edges projected, finish the sketch and then you can extrude the sketch region to complete that feature.

When you hit OK to complete the command, and move to a home view, you will see that your extrude cut matches perfectly the sketch you created with the square on the angled face. However, the sketch you used to create the square, the sketch is still visible. This is because the sketch was never consumed as a feature. Find your sketches folder and you will see one of your sketches still has the visibility turned on. Click the eye next to that sketch and you will have the part you are after.

Here is what the part looks like when complete and the visible sketch has been turned off.

Kevin Ellingson
Technical Specialist
If my post resolves your issue, please click the Accept Solution button.