I'm assuming you mean during Work on Writing? At the link below on this site, you can find several suggestions about this very topic.
https://www.thedailycafe.com/daily-5/work-on-writing/underline-misspelled-words
One thing I might do if the students are having difficulty with words that are either on our word wall or that we've discussed before is this: When I'm reading through their journals, I underline those specific words and have them go back and fix (because we've spent time working on them and students have a model in the room). We might not do this every day, as I don't want them to focus on spelling but on content--but once or twice a week is good.
If you have your students keep individual Word Collectors (WC), this would be a good place to have them add specific words that they use often and may be a bit tricky. The kids can learn to use their WC as another resource.
The "take-away" for me is to remember the true goal of Work on Writing is all about the writing and learning to put ideas on paper. Yes, we can put a little work on spelling into this learning, but let's save the true Word Work for that choice.
