My country is somalia how I can set my credit card to may Apple ID

See where you can and cannot use Apple's media services:

Availability of Apple Media Services - https://support.apple.com/HT204411

and iCloud:

iCloud storage plans and pricing - https://support.apple.com/HT201238

I don't think either is available for Somalia so there is nothing available for you to purchase.

Since there are no Apple stores in Somalia, I assume you’re trying to use the USA or another country’s store. And to do that you’d have to change your country or region, and you’d have to have a card issued by a bank or financial company in that country, with a billing address in that country.

Apple’s online stores are country/region specific and will not allow use with a foreign payment or card.

What Apple actually says is:

Payment methods that you can use with your Apple ID --> https://support.apple.com/HT202631

"Make sure that the billing address for your payment method matches the billing address for your Apple ID. In some cases, you might need to call your bank or financial institution to authorize international or online purchases. You might also need to confirm that the mobile number associated with your payment method is correct."

Nowhere that I have seen does Apple say your card must come from the same country, they just load a bunch of stipulations that mean it is very difficult to use a card from another country.