Pinning
- Long-press a message and pin it; several can be pinned at once;
- Tap the pinned bar at the top of a chat to jump to it;
- Group permissions can restrict pinning to admins.
Replies
- Long-press and choose Reply so the recipient sees the quoted original;
- You can quote the whole message or just a selection;
- Replies in channel comments sync to the linked group.
Forwarding
You can hide the original author when forwarding, and restrict in privacy settings whether forwarded messages link back to you.