Or technically for them.
FAQ
When preparing a story for Instagram, use thecaptions stickerto manually add captions.
fire up the post and select thethree dots icon, then selectEdit.

Sam Edwards / Getty Images
Adjust the captions to your liking, then confirm to save the changes.
Everything else will only show up when viewers grab the “more” option.

10'000 Hours / Getty Images

Anna Denisova / EyeEm / Getty Images