My friend wants to purchase 3d rendered 26 alphabet images from shutterStock. He his freelance graphic designer and want to sell final composed image to their clients with text or message which their clients will provide. 

He wants to know what type of licence he should need for it. Can he purchase hi res images using monthly subscription plan or he should purchase extended licence or copyright licence for each file.  He will also contact shutterstock support. 

Yepp, normal license. Although it would be fun to see the face of the Contributor if he sells 26 enhanced licenses of letters in a batch