Messenger for Facebook. Always appear online?

[pri✍]

So why don't you ask your friend, how she do that?

I don't use FB apk & I don't use FB Messenger, as I don't think it's necessary to install one and thus using space in my memory; I don't do Chat either as I don't see any advantage in doing so, I only use Message inside FB full site.

But to my knowledge & experience, only if I open my Chat, it will show that I'm online (green dot in my Chat). Friends who send Chat to me will be received in my Inbox folder inside Messenger when my Chat is off. So maybe that's why your friends seems not online.

So, do not open your Chat.
For precaution, in case by accident you open it, as it happened a lot, do the following.

Turn On Chat ➤ click cog icon on top right ➤ click Advance Chat Setting ➤ tick Turn on chat for only some friends ➤ write a name of your friend who you know never open their Chat, or a friend who you don't care if they know you're on line/not ➤ Save ➤ Turn Off Chat.

That way you're offline for all except for the one you put their name in there if by any chance you do click Chat On.

The above is my setting as I don't want to chat to anybody.

I believe you get the idea, so you can modify it as you wish if you want to do the chatting.

Whether my above explanation/experience works as well with that FB Messenger I really don't know. You can try it, and if it doesn't work, then uninstall FB Messenger, if you prefer not to be seen online, just use the Message inside your FB.