Here are the steps to text on Instagram:
1. Open the Instagram app on your mobile device.
2. Tap the paper plane or chat bubble icon at the top right.
3. Tap the new message icon or type the person’s name in the Search box at the top.
4. Select the person you want to message and tap Chat.
5. Type your message and add an image, video, audio, or Giphy if you want.
6. Tap Send.
You can also create text posts on Instagram using the "Create" mode feature of Instagram Stories. On the Home page, tap "+" > Story > Aa Create > tap "Aa" > enter and customize your text > send your text to your Story, a friend, or save it to your device to upload as a post.
I hope that helps! Let me know if you have any other questions.