# If ctx is not defined and you are handling a message, use this code
ctx = await bot.get_context(message)
# This is the code needed to give a user a role
member = ctx.message.author # Member object that you want to add the role to
role = discord.utils.get(lambda role: role.name == "Role Name", ctx.guild.roles) # The role object
await member.add_roles(role) # Adds the role to the member