Getting approved for a Walmart Credit Card is not very hard but to qualify for a Walmart Credit Card you need your credit score to be at least 650 or above.
If you have a credit score under 650 you still might get approved for a Walmart Credit Card but if your credit score is 650 or higher then you'll increase your chances of getting approved the first time for a Walmart Credit Card.
If your credit score is under 650 then I would wait until the credit score improved above 650 to apply for a Walmart Credit Card.
I got approved for my Walmart Credit Card when my credit score was 700 but I never tried to get approved for it with my credit score being 650.
You can get a secured credit card through Capital One if your credit is bad and need to improve your credit score.
You put up a deposit for the secured Capital One Credit Card and then use the credit card like normal and pay the payments on time.
Then after a year or so you get the deposit back and your credit score will improve so you can get a regular credit card or a Walmart Credit Card.