Just as athletes are required to complete warm up exercises prior to a race or a game, singers need to prepare their voices ahead of a rehearsal or performance. Singing warm up exercises get the air flowing and relaxes your muscles to prepare for the greater demanding activity to come. It's perhaps the most effective technique to prevent vocal weakness and overuse damage.
It may seem counterintuitive--more exercises to prevent overuse injury? Yes. Your vocal folds are controlled through tiny muscle groups, and when they’re warmed-up they are more elastic, a lot easier to use, and less vulnerable to injury.
Before beginning your singing warm up exercises, carry out some whole-body stretching and relaxation. Start with the "rag doll" exercise. From a standing position, bend forward at your hips, allowing your head and arms to dangle freely. Shake them a bit, then just let them {dangle for one more minute or so. A good exercise to begin with is the "rag doll". Stand upright bending forward from your hips. Then allow your arms and head to droop and dangle for a little while.}Follow that with a stretching exercise for proper posture alignment. Stand with your feet level on the floor, approximately hip-width apart, and your arms at your sides. Bring your arms quickly upward and across your body in a circular motion until they are over your head. Rising onto your tiptoes, take in a good, deep breath as you move your arms up. As you gradually breathe out, bring your arms back down to your sides and come back down to flat feet. Try to keep the chest up and shoulders back, as they were at the top of the stretch, after bringing your arms down. You are now able to begin singing.
The first singing warm up exercise uses a method that goes by various names: buzz, bubble lips, lip roll, or lip trill. Exhale through puckered lips to generate a vibration, sounding a little bit like a power boat or even a "raspberry".
among three tones: the base tone, up a fourth, and back to the base (do-fa-do): within the key of C major, it would be C,F,C. Repeat, moving up a half step each time (C, F, C, then D,G,D, then Eb, Ab, Eb, etc.). You can also execute this on the syllable "ee" or "oo", but the buzz forces you to use good breath support.~The buzz slide will be made amid three tones: the bass tone, which is up a fourth, and then back to the base. (do fa do) so in C major the notes would be C, F and C. You want to replicate this and after that move up a semi-tone each time. Perform this as well with the syllables "oo" and "ee" but the buzzing technique makes for you to use great breath support.}The next singing warm up exercise is the fifth-slide. Start on the fifth tone with the syllable "wee" and slide downward to the base (so-do): in C major again, it would be G, C. Do again on the equivalent tones with "zoo", then move up a half-step and repeat, "wee" and "zoo" on  Ab and Db. Keep on moving up by half-steps.
Next is the five-tone descending scale. Opening on the fifth tone, descend stepwise to the base: so, fa, mi, re, do. First do the syllable "na", next "nay", "noh", and "noo". Move up a half-step and repeat the scale on every syllable.
The fourth singing warm up exercise is a descending 8-tone scale (do, ti, la, so, fa, mi, re, do) on the syllable "noo". Yet again, move up a half-step with every repeat. You can also try further vowel noises, such as "nah", "nay", "nee", or "noh", or use "m" instead of "n" as the opening consonant. Attempt to feel your mask, or higher resonance, when you perform this.
Chase that with a descending arpeggio: do, so, mi, do, on the syllable "nah". Do again on "nay", "nee", "noh", and "noo", after that go up by half measures and repeat on each syllable another time.
The final singing warm up exercise is the octave slide. Bring into play the buzz and start on the base note; slide up an octave and back down to the base: do, do, do. Repeat on "oo". Go up a half-step, do the buzz, and followed by "oo". Persist moving up by half-steps.