Both do the ‘same job’ but a service is usually religious where as a ceremony is not. These booklets or programs are for your guests to follow the proceedings without hiccups and having to find hymns or songs in hymn books or via a screen.
They detail the order of the proceedings and what is happening at any-one time (especially useful to those who don’t have the best view’ of what’s happening). They list readings and authors, hymns and songs and those reading/singing.
Always remember that if you’re printing the lyric to songs/hymns etc under copyright, unless your venue has its own license, then you should obtain the necessary permissions and pay any associated fees.
The booklets often include details of the Bridal party and sometimes dedications to those not able to share in the celebrations.