Hi @Jay5EF2, welcome to the community!
Could you let us know which version of Lightroom you’re using and whether you’re on desktop or web? If you’re on desktop or web, you can simply export your photo and then post it to Instagram.
If you’re using Lightroom Mobile, you can share directly to Instagram using the Share button:
Tap the Share icon at the top right. (If you don’t see it, return to Photos view, select All Photos, choose the photo you want, then tap Share.)
In the share sheet, tap the Instagram icon, add your caption and hashtags, and tap Share.
Your photo will appear on Instagram with all the edits you made in Lightroom.
Thanks so much!
Alek