Beginner Role: Any
You can play Teemo in any League of Legends position – even Jungle if you’re careful. While there’s a lot of controversy around Teemo, he’s still one of the funnest LoL champions to play on top of being a great pick for beginners. I promise this isn’t a troll entry – hear me out!
Besides his basic attacks dealing poison damage over time (great for dealing massive damage safely over time and securing kills), his main ability is a blinding dart which blinds an enemy champion or monster and stops them being able to hit you with basic attacks for a short while. This makes Teemo great for people who find themselves being jumped on regularly (everyone focuses on griefing Teemo!) and need an ability that gives them some breathing space while they run away or to tackle a big monster in the Jungle. Not only is the blind dart useful for saving your skin, but you can play Teemo in a support role at a beginner level to stop your ADC getting hit as well. Teemo has multiple uses, and you can even use his mushrooms to keep your lane safe and potentially get the upper-hand on an incoming enemy trying to gank your lane.
Beginner Role: Mid & Support
Morgana is one of my favourite characters in the whole of League of Legends. She’s great for Top as well when you get better with her, but for a beginner let’s stay in Mid and Support in terms of picking her. Morgana’s shield ability will absorb a chunk of magic damage, and will nullify any spell effects such as stuns/silences while it’s active. This makes her a great pick for Mid lane where you’re usually against another magic user, which means you can take free hits and avoid being stunned etc.
She’s also great for support because of her stunning orb which will root a champion in place, as well as a then a toxic pool to lay down which deals damage over time. If you can time her pool to activate straight after you stun someone, you can deal a lot of damage this way and make it easy for your ADC to finish them off. Her ult throws dark tentacles at nearby enemies, and stuns them after being connected for a few seconds. This can be useful for saving your ADC if you need to give them time to escape, or pressure the enemy into backing off.