I cannot add a credit card to my wallet so cannot install applepay. What can I do ?

This means that Apple pay is not currently offered in your country where your Apple ID is registered to.

Here's a list where Apple pay is supported Countries and regions that support Apple Pay - Apple Support if your country is not in the list then it's not supported.

To change your Apple ID country or region, please check this article Change your Apple ID country or region - Apple Support

To make it more clear, if you purchased your iPhone from Dubai and you reside in Dubai but your Apple ID region is set to Mauritius (Which isn't supported) then it'll not give you the option to add your card.

Your Apple ID would then show you live in Dubai?

Make sure your home country shows here:

Countries and regions that support Apple Pay - Apple Support

The only pother thing I think of is to click the little x on the cards, but if the plus in the upper right hand corner doesn’t get you anything I’m not sure how to help you :-/

Sorry JMPatu, I think I’ll have to let someone else step in here. Maybe they can help you.

Sorry, I should have worded that better.

Where country is your Apple ID registered to?

I don’t see see your second picture, but typically those first few cards you see are a tutorial of sorts. The + button is the way to add the cards - it will ask what type of card you are trying to add, and go from there.

Try the plus button in the upper right hand corner.

If you hit cancel and scroll to the right, what do you see?

And what country are you in?