I want to purchase a subscription for US apps, when I try to enter my India CC details it is not allowing, can any one help me

It is not possible, sorry.

See -> About billing for Apple subscriptions and media products in India

About billing for Apple subscriptions and media products in India - Apple Support

See -> Payment methods you can use with your Apple ID

Payment methods you can use with your Apple ID – Apple Support (UK)

India

•               Apple ID balance (from adding funds)

•               Net Banking (adding funds only)

•               UPI (adding funds only)

You can use / pay with your Apple Account balance, see: Add money to your Apple Account balance

Add money to your Apple Account balance – Apple Support (UK)