I can't believe I'm going to ask this question, but I'm really clueless about it

Forgive, it's only my second year teaching, and I don't have an education degree. I'm working on it now though and I have a year left.
I've heard several teachers mention that they have students journal in the beginning of the day and many have them write the morning message.
Can someone tell me what the purpose of writing the morning message is? If I wanted my students to do that, what is it that I should be doing to the morning message? Is it for handwriting practice? I'm sorry this sounds so ignorant
I can see Journaling, and that's what I used last year. Should I do the morning mesage instead? I'm just trying to think of a short 15-20 minutes morning activity for the students to do, since they come in the room at all sorts of times. Thanks guys