The selection makes a GET request with selected Tin :) This is how you will get the json response back, and therefore, no need for BeautifulSoup.

from requests import Session

s = Session()
headers = {'User-Agent': 'Mozilla/5.0 (X11; Linux x86_64) '\
                         'AppleWebKit/537.36 (KHTML, like Gecko) '\
                         'Chrome/75.0.3770.80 Safari/537.36',
          'Accept': 'application/json'
}
# Add headers
s.headers.update(headers)


BASE_URL = 'https://mahagst.gov.in/sap/opu/odata/sap/ZMSTD_KYT_SRV/TinDetailSet'

params = {
    "$filter": "(Tin eq '27680809621V')"
}

r = s.get(BASE_URL, params=params)

data = r.json()
print(data)

This is how I found out the URL and params

And the data return is a beautiful json(dictionary) :)

The data is a dictionary and list. So you can use your Python skills to get the variables out. e.g. data['d']['results'] :) Hope this will help you.