You can’t directly see if someone has Snapchat Plus, since it’s private.
But a few hints may suggest it:
They have exclusive features like custom app icons, special story badges, or the “Best Friends Forever” pin.
A star badge ✪ may appear next to their display name (if they enable it).
Unless...
iPhone: Open App Store → search Instagram → tap Update.
Android: Open Google Play Store → search Instagram → tap Update.
New features appear after updating.
Use iTunes/Finder: Connect iPad to computer → put iPad in Recovery Mode → choose Restore.
This erases all data and removes the password.
You’ll need your Apple ID to set it up again.
Check Recently Deleted in Your activity.
Request Download Your Information in settings.
Check Messenger if accounts are linked.
Fully deleted chats can’t be recovered.