Can I create an NPC (Non-Player Character) that talks or gives quests?
Edited
Try Tynker's Mods Editor (Project > Create Project > Minecraft > Create Mod).
https://www.tynker.com/dashboard/student/#/minecraft/mod/bedrock
Use a block like this one! See if you can give the player a reward for completing your quest, too.
You can change the look of NPCs using Tynker's mobs editor (Project > Create Project > Minecraft > Create Mob). Find NPC mobs from Tynker's community at the link below.