Hi Sagar
as you spoke of a client... I suggest you are a employee of (some kind of) a professional development company.
I would expect that either the customer provides you with an appropriate environment in Azure, or "you" as the service provider have an appropriate environment.
to your questions:
to 1.) you have to get in contact with your account manager (MSFT) and tell him about your project, if it is eligible for a sponsorship, he will provide you the correct steps how to get it.
to 2.) not an option for professional development
to 3.) from my pov: the only option for a professional app development company to run their test/dev environment.
I hope my answer is helpful to you,
Your
Bjoern Peters
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