To sign up in Stripe, click on the link here
You can find the supported currencies & countries from the links here
Go to your store dashboard then click on Payment

Toggle on the Online Payment
Click on Settings
Click on Payment providers
Choose Stripe - Card (If it doesn't appear at first, click on View all)
You'll find the supported countries and cards, then Integrate
These are the requirements you need to fill on your store from your account on Stripe
Log in to your account on stripe, Click on API Keys, to get Published & secret keys
Go back to your store, fill in the required info you got, activate the button, then Next
Activate the buttons, then Finish