Tara, the Mother of all the Buddhas, emanates in countless forms to help sentient beings.
In her most wrathful black form, the 7th of the 21 Taras, she overcomes every evil, every enemy, obstacle, negativity — and even curses or evil forces.
All Taras protect.
As Black Tara, in her most wrathful form, she tramples and burns them completely so they can never harm us.
Her mantra is among the most powerful of protections:

oṃ tāre tuttāre ture sarva vidyā avarṇā ye bhye phaṭ svahā

 ओं तारे तुत्तारे तुरे सर्व विद्या अवर्णा ये भ्ये फट स्वहा ॥

For protection or just as a devotional practice, chant her mantra in Sanskrit, the powerful mother language. Empowerment is not required to chant any mantra of Enlightened Mother Tara.
Chant it any time you feel threatened, nervous, ill-at-ease, or in need of the nurturing protection of a wrathful mother.
Black Tara is still Mother Tara — just hulked up with power so that she can always protect you.

Chant her mantra ideally 21 times or 108 times, visualizing her as an energetic, black form of Tara.
She is the color and nature of the deep space cosmos, black as a starry night sky.
She can be sitting, standing, or even dancing with energy.
Her whirling fire surrounds you in a protective shield.
As you chant, feel confident in her protection and power.
Notice the vibrations of your chanting.
Concentrate on the powerful syllables.

Although all Buddha's including Tara can emanate in any form, there are two main aspects of Black Tara. In the Atisha or Nyingma lineages she appears seated similar to Green Tara. Instead of Green, she is Black, which is the color of wrathful enlightened activity, her mouth slightly open and wrathful. Like Green Tara, she holds a lotus, but on the top of the lotus is a wisdom sword.

In the Surya Gupta Lineage she is dancing and very wrathful, with four arms.
One arm holds a wisdom sword, another a Dharma Wheel, and the Lotus flower she holds in another hand has a vajra on top. The fourth hand is held out in a wrathful mudra. She stands in the heroic posture, and her red hair is upright.
For more information on this lineage of Black Tara, including the slightly different Surya Gupta mantra, see the video linked in the information icon above.
Whether seated, or standing, black Tara can be visualized surrounded by wisdom flames.

Chant along now, with the beautiful voice of Hrishikesh Sonar, the sacred and powerful mantra of Black Tara, Destroyer of Enemies and Evil, who Crushes all Adversaries to our Dharma practice.

Mantra 108 Times:

oṃ tāre tuttāre ture sarva vidyā avarṇā ye bhye phaṭ svahā

 ओं तारे तुत्तारे तुरे सर्व विद्या अवर्णा ये भ्ये फट स्वहा ॥