@vamsi_varanasi, just re-posting what was posted under the other topic, so it is easy to find for others who might be looking for this. Please mark this as the accepted solution, if you believe this solves your problem.
It is quite straight forward. When you have a table in a variable (e.g. %Table%), you can simply push it into a custom object and then convert it to Json.
Here's a quick sample. I created a simple Excel file with the following table:
I then read the file, extracting data so that the first row is a header row. Here's the result from PAD:

I then used the following three actions (you can copy and paste this directly to PAD):
SET NewVar TO {{ }}
SET NewVar['Table'] TO Table
Variables.ConvertCustomObjectToJson CustomObject: NewVar Json=> CustomObjectAsJson
Looks like this in PAD:

What it does is as follows:
- Create a new empty custom object named %NewVar% (you don't really need to create a new object if you already have one, though)
- Add a property named 'Table' to the custom object with %Table% as its value*
- Convert the custom object to Json
* Note: If you already have a property with the same name in the object, it will be overwritten. If you do not, it will be added as a new property.
The custom object (%NewVar%) will look like this:

The 'Table' property inside of it will look like this:

And the Json data after conversion (%CustomObjectAsJson%) will look like this:
{"Table":[{"Key":"One","Value":"1"},{"Key":"Two","Value":"2"},{"Key":"Three","Value":"3"}]}
As you can see, it basically is converted into a list of objects, with each row being a list item, and each value being added with the column names as keys.
This can then easily be parsed by Power Automate.