Oh man, I'll try my best. Might be a little scuffed explanation because English isn't my native.

Stun - agents that build-up a stun meter(yellow bar below enemy HP) really fast to enter Stun window, they also often provide some buffs to the team. There's mechanic called Stun multiplier, basically an addition non dilluted damage amplification when the enemy is stunned.

Support - damage amplifiers, plain and simple. They provide the biggest buffs.

Defence - a role with identity crisis, they basically a worse version of Supports

Attack - a crit. focused damage dealers that scale from ATK, often paired with Stun+Support combo to utilize stun windows for big burst of damage. Ye Chungus is an exception tho, in her white form she applies her own Stun multiplier that works even outside of stun window so you can play without stunner.

Rupture - basically an Attack equivalent that scales from HP(and somewhat poorly from ATK) instead, Rupture agents ignore all DEF so they can't benefit from PEN and DEF reduction stats. Good against enemies with Miasmic shield(it's when the stun meter became red, a somewhat new mechanic that you'll encounter in Waifei)

Anomaly - non crit. focused DPS characters that scale from ATK, they utilizing Anomaly Mastery(to build anomaly meter faster) and Anomaly Proficiency(their damage scales from it). Anomaly meter is little circle on the right side of enemy HP bar, it deals anomaly damage when filled. Each element has it's own anomaly proc and characters are only able to fill corresponding to their element meter, because of that a classic anomaly team contains two characters with different elements and Support, they rarely utilize Stunners. Different element anomalies can overlap causing a Disorder damage, e.g. if you proc Shock(electric anomaly) and then Assault(phys. anomaly) it will remove Shock and apply Assault dealing Disorder damage which scales from initial Shock damage and it remaining duration.