There are a few ways to add spell check in InDesign. One way is to go to the "Edit" menu and choose "Check Spelling." This will open a dialog box where you can choose to check the entire document or just a selected portion.
Another way to spell check is to first select the text you want to check, then go to the "Edit" menu and choose "Check Selected Text." This will open a dialog box where you can choose to check the entire document or just the selected portion.
You can also add spell check to your InDesign preferences. To do this, go to the "Edit" menu and choose "Preferences." In the preferences dialog box, choose "Spelling" from the list on the left. Then check the "Check spelling as you type" and "Check spelling as you open a document" options.