My dog licks excessively

I have a 9 year old lab mix, that I rescued from being a breeding dog. She’s the sweetest girl ever and definitely has some anxiety. I’ve known dogs to mix their paws when they’re anxious, but she never licks her paws actually, but licks everything else. 1.) licks people as much as they’ll let her 2.) when she’s excited she’s just licking the air 3.) when she approaches people she’s licking the air 4.) when she’s outside and wants to be let in, she stands there licking the window

There’s a lot more but this is the general highlights. We joke her tongue is out of her mouth so much she’s like a snake and uses her tongue to see. Why does she do this? Is to get people’s attention? Can we train her not to do it? I feel bad when a guest sits on the couch and she immediately gets in their face licking. Or the amount of times for five minutes I’ve had to continuously push her away from trying to lick my legs (whether I have long pants or shorts on)