Most credit cards offer an APR range (20.49%-29.99%, for example) and issuers will set the interest rate for each applicant after reviewing their credit history. Applicants with good to excellent credit scores will typically get the lowest rates.
A card's APR can range from just under 10% on specialized low APR credit cards, to around 30% on credit cards for low or no credit. Anything under 15% is optimal, but many cards, especially no-annual-fee cards, will often start at 18%-20%.
If the APR is a priority, look for specialized, low APR credit cards with very limited ranges, such as 12.00% to 18.00%; just know that benefits and rewards will be very low or none at all with these cards. If you're pretty certain you'll get a low rate, look for cards that start at or below 20%.