I want to know where i get mongo db database url i am deploying bot in telegram.
Hi @Kushagra_Maurya, welcome to the community. 
Please take a look at this guide explaining how to deploy a free tier cluster on MongoDB Atlas.
I hope it helps.
In case you have any doubts, please feel free to reach out to us.
Thanks and Regards.
Sourabh Bagrecha,
Curriculum Services Engineer