The indictment against 36-year-old Ivanna Lisette Ortiz of Orlando was unsealed on Wednesday by a judge.
Ortiz, appearing in court wearing yellow jail clothes, spoke only to her lawyer, who entered a not guilty plea for her.
The judge then ordered her held on $US2.6 million ($A3.7 million) bail.
The move came a day after another judge ruled that Ortiz is mentally competent to stand trial.
The secret grand jury proceedings were held as the woman was undergoing months of psychiatric evaluation, and the case that appeared stalled - possibly permanently - is now on a fast-track to trial.
"This is a person who wanted to kill Rihanna," Deputy District Attorney Alexander Bott said outside court.
"Everyone else was collateral damage."
Ortiz was previously charged in March with Rihanna's attempted murder and more than a dozen other felony charges, and she pleaded not guilty.
No one was injured but bullets tore through an Airstream trailer that the singing superstar and A$AP Rocky were in at the time.
Shots also struck the wall of their nursery where their three small children were with their nanny.
The grand jury indictment supersedes the original charges.
And the secret proceedings allow prosecutors to skip California's preliminary hearing process, where evidence must be presented publicly to see if a trial is merited.
The indictment also charges Ortiz with 10 counts of assault with an assault weapon and three counts of shooting at an inhabited dwelling or camper.
She could get life in prison if convicted of all counts.
Reports have been sealed on the psychiatric evaluations that paused the case shortly after it began, and there was no public discussion of the details of her mental state.
Prosecutors have not said anything about a motive or cited any connection between Rihanna and Ortiz, a longtime licensed speech pathologist with no prior criminal record.
Authorities allege she drove a Tesla from Orlando to the Beverly Hills-area property of Rihanna and her rapper partner A$AP Rocky on March 8, pointed an AR-15 style rifle out the window and fired at least 20 rounds toward the property and a neighbouring house.
Investigators found bullet holes in the trailer and on the exterior wall of the home's second-floor nursery, where the children and nanny were present. Rihanna's mother and several staffers also were in the home.
Investigators said that after her arrest later that day, Ortiz told them: "I wasn't attempting murder."
A nine-time Grammy Award winner, Rihanna has had 14 No. 1 hits on the Billboard Hot 100, including We Found Love, Work, Umbrella and Disturbia.
