There are lots of visible differences between litecoin and bitcoin..Litecoin was created by Charles Lee in an attempt to create an improved crypto that is similar to bitcoin in essence but without all the excessive bits . Some comprehensive differences between Litcoin and bitcoin are as follows.( I am using data from coindesk.com)
Algortihm- Bitcoin uses a SHA-256 which has great capabilities of parallel processing. Litecoin uses an algorithm named SCRYPT which has similar patterns to SHA-256 but hash processing are more serialised.
Transaction Time- Litecoin is more faster than bitcoin which allows litcoin to handle more blocks in the same amount of time bitcoin needs.
Coin limit- Bitcoins limit is 21 milliin where litecoin has a limit of 84 million.
Block time- Litecoin takes 2.5 minutes to confirm a block where Bitcoin needs 10 minutes.
Market cap- Bitcoins marketcap is over 10 billion USD where litecoins cap is more than 540 million.
Block reward details- Bitcoins are halved around 0.21 million blocks and litecoins has a halve ration of 0.84 million blocks..
There are plenty other differences between them but these are more notable.. If you want to invest or anything don't take ideas from this answer.. Do a more in-depth analysis..