DefenderDefenders take a lot of damage, mark targets and protect the rest of the party. If enemies they target try to attack another member of the party the defender will attack to stun, damage or taunt enemies to protect their companions.
LeaderLeaders are healers, buffers and debuffers. Their powers support the party's success either by healing damage taken, preventing damage from being taken or increasing the damage enemies take.
ControllerControllers influence fights by controlling either the field of battle or targets directly. Their role is to ensure threats are minimized or handled efficiently.
StrikerStrikers specialize in mobility and damage output. These combatants focus on disposing threats as quickly as possible by doing as much damage as they can, as quickly as they can, without enemies retaliating.
These website are extremely helpful try to learn as much as you can before choosing your first two characters:
Control Wizard
 https://neverwinter.gamepedia.com/Control_Wizard
Devoted Cleric
https://neverwinter.gamepedia.com/Devoted_Cleric
Great Weapon Fighter
https://neverwinter.gamepedia.com/Great_Weapon_Fighter
Guardian Fighter
https://neverwinter.gamepedia.com/Guardian_Fighter
Hunter Ranger
https://neverwinter.gamepedia.com/Hunter_Ranger
Oathbound Paladin
https://neverwinter.gamepedia.com/Oathbound_Paladin
Scourge Warlock
https://neverwinter.gamepedia.com/Scourge_Warlock
Trickster Rogue
https://neverwinter.gamepedia.com/Trickster_Rogue