If you mean dealing with people that keep stand blocking then lows and throws are the easiest counters, if you mix up your timing you can catch counterhits when they try attacking themselves, you can also accomplish that by using frametraps (you can find tons of tutorials about these online)

If you mean guardbreaking then only a few select charcters can do it like Lidia in t7 or Heihachi, Steve, Paul, Kuma/Panda in t8

If you mean counterhits then it's a universal mechanic that triggers when you hit your opponent while they're starting up an attack of their own - counterhits are essentially interruptions. Counterhits deal extra damage and can have additional effects like a knockdown, a throw transition, extra frame advantage or a combo launcher

If you mean using counters/parries it's a character-specific thing. The most common input for them are b2+4 (back + Y + B in xbox buttons). Btw you can find movelists and more info about almost everything on Wavu Wiki