How do you pm someone?

??????????

When you click someone's avatar it will say "start a conversation "

Thankyou

I'm on a tablet it's not giving me that option. I haven't used my account in a couple years is that why?

It's probably because your account isnt very active sometimes permission settings aren't given to older users who don't have a lot of content
You'll have to post for a while before obtaining your conversation messages