Hello Parveen,
Azure PAYG subscription do not support spending limits as you can check here: https://azure.microsoft.com/en-us/support/legal/offer-details/
Those account types that support it are primarily for MSDN / Visual Studio subscribers or Education.
What I would recommend you do is to investigate Azure Budgets and Budget alerts (part of Cost Management). You could set a budget to e.g., 200 USD and set "actions" and notifications when you reach a threshold in each month, for example 75% of the budget cap.
This won't work the same way as spending limit (meaning that your will be charged for more than your "budget" if you don't take any actions) but at least you will have a better control on how is your monthly spend evolving and what actions you can take (like shutting down VMs you don't use outside business hours, etc.).
Hope this helps.