It is very important to properly warm up your voice before singing! Not only does it help you to sing better, but it makes sure that you take care of your vocal chords (the tissue that vibrates to create your voice) and the inner muscles of the larynx (the muscles that control your vocal chords). When you warm-up, you stretch and relax the vocal chords and larynx muscles, making them ready for singing. It's like warming up before a soccer game. You don't want to pull a muscle!
Here are some YouTube channels that provide really excellent warm-ups you can do at home.
- The Singing School: This channel has a great body warm-up (10 Minute Vocal Warm-up) and a couple of great vocal warm-ups, solfege practice, and sight reading practice. I recommend you start with the body warm-up, pick one of the vocal warm-ups, and one of the solfege or sight reading warm-ups.
- KT Vocal Studio: This vocal studio has a lot of great warm-ups for different voice types, as well as some vocal tips.