VPIP stands for Voluntarily Put chips in pot. This stat shows the percentage of time you make calls or raises before the flop.

if a player’s VPIP is 1%, they’re probably only going to be playing(calling or raising) with Aces or Kings. Alternatively, if their VPIP is 100%, they’re playing with every single hand they’re dealt. Every time you make a preflop raise, you will add to your VPIP percentage. Every time you call a preflop raise, you will again add to your VPIP percentage.

PFR stands for Pre Flop Raise.
This stat shows the percentage of the time a player raises before the flop.

Every time you make a preflop raise, it counts toward your PFR. This can be a simple raise to 4bbs, or it could be a 3bet or 4bet. Basically any time you enter the pot preflop with a raise, you’re contributing to your PFR stat.

The proportion of hands the player won out of all all-in showdown situation, no matter if the concerned player was all-in first and called, or if the concerned player called another player’s all-in bet. A hand must went to showdown to be considered in this metric. This metric is a good indicator of variance.

Player A have 1000 chips, and player B have 500 chips. Player B bets 500 and player A calls, if player B wins the hand, then the hand would count as player B winning an all-in and player A losing an all-in. If player B bets 500 and player A folds, then the hand would not count as player B winning an all-in regarding the all-in win rate statistic.
Let’s assume that player A went all-in for 18 times in the last 20 hands, in which player A took down the pot(not being called) 8 times, was called and won 6 times, and was called and lost 4 times. His all-in win rate would be 60%(6/(6+4)), as the 8 times where he took down the pot without showdown would not count towards this statistic.

The pot size is based on the amount in the pot after the player completes the current outstanding bet, which is the current pot amount plus the highest outstanding bet.

The pot size is based on the amount in the pot after the player completes the current outstanding bet, which is the current pot amount plus the highest outstanding bet. Then, the 1/2x and 2/3x multipliers would be applied.

In a 6 player game with small blind 50, big blind 100 and no antes, early position raises to 550 and everybody folds to the big blind. Here, the current pot is 700. If the big blind chooses to raise 1xPot, then he needs to first complete the current outstanding bet, which is 450, and then raise the new pot size, which is 450+700=1150. So, by clicking 1xPot, the big blind would be effectively raising to 1150+450=1600.
Here, the 1/2xPot sizing would be 1150*0.5+450=1025.
The 2/3xPot sizing would be 1150*0.667+450=1216, rounding down.