Most people don't have to worry if their signature is sloppy -- but if it's your name on the US dollar bill, it's best to practice, says US Treasury Secretary Janet Yellen.

"It’s customary that Treasury secretaries provide their signature to be featured on our nation’s currency," said Yellen, the first woman to hold the office, at a ceremony unveiling new notes bearing her name.

"You’d think this would be a straightforward process, but the founding fathers did not account for what seems to be a common attribute for Treasury secretaries: terrible handwriting."

Yellen had previously remarked in a TV interview that two of her predecessors, Tim Geithner and Jack Lew, had signatures "so illegible that people made fun of them."

Geithner "famously had to change his signature in order to make it legible," she joked Thursday.

"I’ll admit: I spent some quality time practicing my signature," she added.

In addition to the first female Treasury secretary's name appearing on them, the new notes unveiled Thursday will also be historic for including two women's signatures: that of Yellen and US Treasurer Lynn Malerba.

"Today is not about me or a new signature on our currency. It's about our collective work to create a stronger and more inclusive economy," Yellen said in a speech at the Fort Worth, Texas money printing facility.

The notes are set for delivery to the US Federal Reserve this month and will be in circulation starting in early 2023, according to the Treasury Department.

Currently, women represent about 62 percent of the Treasury workforce and hold positions of power, she said.

But much more still needs to be done, Yellen added.

"I hope that today is a reminder of the road we've traveled on equity and inclusion. And I hope it motivates us to continue to move forward," she said.

Malerba's signature also marks the first time US currency will feature the signature of a Native American woman.

"This moment is history," said Malerba.

The first notes bearing Yellen and Malerba's signature coming into circulation will be $1 and $5 bills.

Apart from the site in Texas, the only other greenback printing facility is in the US capital Washington.