What is the exact translation of "Vayikra v'Shem Hashem"?
Rashi (citing Targum Onkelos) and Targum Yonasan: Moshe called out in the Name of Hashem.
Rashbam: Hashem called out (as He passed Moshe) by His Name. 1
Seforno: Hashem, mentioned earlier in the Pasuk, called out the Name of Hashem (His Divine Attributes).
Da'as Zekenim, Hadar Zekenim (33:21): He informed him with which name He will go with him (in the Midbar).
As He told Moshe earlier (See 33:19 [Rashbam]).
What does it mean "va'Yisyatzev Imo Sham"?
Moshav Zekenim: Hashem showed Moshe how Yisrael stand and the Shali'ach Tzibur reads the 13 Midos. This implies that the Shali'ach Tzibur alone says them; this is not the custom.