Hello Vijaysinh,
Thank you for reaching out to the Google Ads API support team.
Unfortunately, at the moment Keyword Plans in the API and the UI are not fully compatible.
Thus, you need to choose if you wish to use only the API or only the UI to manage your keyword plans, but you cannot use both.
We plan to improve them to be more compatible in the future.
Best,
Mattia Tommasone
Google Ads API Team