To edit the appearance of your CCLI license number in your lyric slides, go to the Edit tab in EasyWorship, 

select Options and then click on Song. 

At the bottom of the window, under Copyright Info, is a field for License Info. 

Type your CCLI license number once and click OK and it will appear automatically in each song that is copyrighted. 

By clicking on Copyright Font in the Options, you can also edit the Font, Outline, Shadow and Margins.