Pit and Charizard is a interesting matchup. Looking at you,
Handy Man
The way the matchup works is playing the bait and punish game on each other. Both of them have similar kill options, yet they have different attributes (weight, speed, knock back, etc.)
The way the matchup is played is Pit can rack up the damage quickly, while Charizard goes for the hard reads and can take advantage with the rage factor.
What Charizard needs to look out for from Pit are his 3-hit jabs, fair, nair, arrows, side B, uair, and grabs.
Neutral
In the early games, you want to deny Pit from trying to grab you. How do you prevent it? Simply go for some retreating fairs to space yourself out, and if Pit gets close enough withing jab range after he whiffs the grab, go for the 3-hit jab. Every once a while, mix it up by tossing out a dtilt. Even though they may put up their shield to block it, you can condition them to dash shield and then go for the dash grab. A cool way to punish Pit's grab is sidedodge into mutltiple utilts. In other words if Pit whiffs the grab while you sidedoge, Pit should be close enough where you can use a few utilt strings to a possible uair on him.
A fun fact that I wantto mention is Charizard's fair can actually outprioritize Pits rising nair if you time it well.
Landing
This is by far one of the most difficult things to deal with in this matchup. Due to his large size and Pits quick dash speed along with multi-hitbox aerials as well as his usmash. The only way Charizard can land safely is throw out some fast fall nair, or go for a falling fair to cover yourself. The best way to mix up the landing is go for a b-reverse flamethrower to prevent Pit from hitting you with his aerials (if spaced properly. Every once a while, go for a rock smash. Although I don't recommend using it a lot since it's unsafe most of the time against an opponent that can shield the rock smash and punish it accordingly. The safest way to land is to grab the ledge as if your fighting Rosalina who's trying to juggly you around with uairs.
Arrows
When Charizard is trying to get back on stage, you can airdodge to avoid the arrows. Flare Blitz can go right through the arrows, but make sure your close enough to grab the ledge.
If Pit is playing campy by shooting arrows on stage, you can adapt to the situation by dash shielding and punish him with a grab/tilt/jab after he fires the arrow on your shield.
Stage Choices
Pit is one of those characters that can adapt to any stage, whether it has jank, neutral stages with platforms, or simple flat stages. Obviously, you would want to take Pit to Duck Hunt, thanks to the tree branch thats near the top of the ceiling blast zone. Also, he can survive a bit longer from Pit's upperdash arm, thanks to the high ceilings.
If the Pit player were to ban Duck Hunt, then take him to Battlefield or Dreamland. The blastzones for both Dreamland and Battlefield are wide, you can survive a bit longer from Pits fthrow. Combine that with the DI, you can live up to 160% or higher, depending on how often Pit stales the fthrow. Keep in mind that Charizard can tech the platforum after Pit dthrows, that way you could potentially interrupt Pit's follow ups.
Overall
I want to say its 30-70 in
favor, due to Pit having faster frame data, easier time to juggle, and stronger offstage game. The only thing Charizard has going is he is a heavy character that can last a very long time, can kill earlier (combine it with his rage), but you need to land the hard reads.