There are no special prayers or blessings that must be recited while lighting a Yahrzeit candle. Lighting the candle presents a moment to remember the deceased and time for introspection.
The Lord is my shepherd; I shall not want.
He maketh me to lie down in green pastures;
He leadeth me beside the still waters.
He restoreth my soul;
He guideth me in straight paths for His name's sake.
Yea, though I walk through the valley of the shadow of death,
I will fear no evil,
For thou art with me;
Thy rod and thy staff, they comfort me.
Thou preparest a table before me in the presence of mine enemies,
Thou anointest my head with oil; my cup runneth over.
Surely goodness and mercy shall follow me all the days of my life;
And I shall dwell in the house of the Lord forever.
I will lift up mine eyes unto the mountains; From whence shall my help come?
My help cometh from the Lord, Who made heaven and earth.
He will not suffer thy foot to be moved; He that keepeth thee will not slumber.
Behold, He that keepeth Israel Doth neither slumber nor sleep.
The Lord is thy keeper; The Lord is thy shade upon thy right hand.
The sun shall not smite thee by day, Nor the moon by night.
The Lord shall keep thee from all evil; He shall keep thy soul.
The Lord shall guard thy going out and thy coming in, From this time forth and forever.
A Song of Ascents. Out of the depths have I called Thee, O the Lord.
L-rd, hearken unto my voice; let Thine ears be attentive to the voice of my supplications.
If Thou, the Lord, shouldest mark iniquities, O L-rd, who could stand?
For with Thee there is forgiveness, that Thou mayest be feared.
I wait for the Lord, my soul doth wait, and in His word do I hope.
My soul waiteth for the L-rd, more than watchmen for the morning; yea, more than watchmen for the morning.
O Israel, hope in the Lord; for with the Lord there is mercy, and with Him is plenteous redemption.
And He will redeem Israel from all his iniquities.
Maschil of David, when he was in the cave; a Prayer.
With my voice I cry unto the Lord; with my voice I make supplication unto the Lord.
I pour out my complaint before Him, I declare before Him my trouble;
When my spirit fainteth within me--Thou knowest my path--in the way wherein I walk have they hidden a snare for me.
Look on my right hand, and see, for there is no man that knoweth me; I have no way to flee; no man careth for my soul.
I have cried unto Thee, O the Lord; I have said: 'Thou art my refuge, my portion in the land of the living.'
Attend unto my cry; for I am brought very low; deliver me from my persecutors; for they are too strong for me.
Bring my soul out of prison, that I may give thanks unto Thy name; the righteous shall crown themselves because of me; for Thou wilt deal bountifully with me.
Kaddish occupies an absolutely unique place in Jewish life and Jewish history. It is one of the most profound and stirring prayers in all of Judaism, and ironically, it may be the most misunderstood. Most people think that Kaddish is a prayer for the dead, in fact, it is a prayer for the living.