Our Sages enacted that Hallel should be recited on several days throughout the year. In addition to these mandatory days the Gemara (Ta’anit 28b) explains that saying Hallel on Rosh Hodesh is a Minhag and is therefore recited in an abridged format. The rabbis debate whether the abridged Hallel of Rosh Hodesh warrants a blessing and there are three principal approaches to this question. Rabenu Tam explains that even a custom warrants a blessing, and he rules the Hallel of Rosh Hodesh should be recited, whether one prays in a Minyan or alone. The Rambam rules that a blessing should never be said over the abridged Hallel of Rosh Hodesh as it is simply a Minhag. Finally, the Rif takes an intermediate stance by saying that a blessing should be recited only in a Minyan, but not by an individual praying alone.
The Bet Yosef quotes the Ran who testifies that the practice in Spain was to follow the opinion of the Rif. Rabbi David Ovadia says that a blessing should be said whether or alone or with a Minyan, like Rabenu Tam, although most Sephardic communities also follow the Rif’s approach. Although it is unclear what the Bet Yosef himself practiced, he mentioned that the custom in Israel was to never recite a blessing on Hallel of Rosh Hodesh, and indeed this is the custom of Sephardic communities from Syria, Iraq, etc.
Finally, the Moroccan custom is to recite a blessing over the Hallel on Hallel, but only in the a Minyan, as per the Rif. Furthermore, Moroccans recite the blessing “Ligmor Et HaHallel” when the complete Hallel is said, and “Likro Et HaHallel” when the abridged Hallel is said.
Summary: The Moroccan custom is recite a blessing on Hallel of Rosh Hodesh, specifically “Likro Et HaHallel”.