Trump White House aide Madeleine Westerhout testified that Trump did not use email or a computer.

"What is Mr. Trump's preferred method of communications?" prosecutor Becky Mangold asked.

"He liked speaking to people in person or over the phone," Westerhout said.

"Did Mr. Trump use a computer?" Mangold asked.

"Not to my knowledge," Westerhout said, adding Trump did not use email.

"He liked hard-copy documents," Westerhout said.

Westerhout testified that Trump paid attention to details and signed things himself, preferably with a Sharpie.

"He preferred to sign things himself," Westerhout said.

"Did he typically read things before signing them?" Mangold asked.

"Yes," Westerhout said.

Jurors saw a map of the West Wing of the White House to demonstrate where Madeleine Westerhout's desk was in relation to the Oval Office.

"That is the area known as the outer oval office -- that is where the presidential secretaries or assistants sat," Westerhout told the jurors, highlighting the location of her desk.

Westerhout said she sat near John McEntee, Hope Hicks, and Keith Schiller, but no one sat closer to Trump's desk in the Oval Office than she did in the early days of the Trump administration.

"Who was the focus of your job?" prosecutor Becky Mangold asked.

"The president," Westerhout responded.

Before she worked in the White House, witness Madeleine Westerhout worked at the Republican National Committee.

On the stand, she testified about the aftermath of the release of the infamous "Access Hollywood" tape.

"It was a tape of Mr. Trump and Billy Bush," she said. "At the time I recall it rattling RNC leadership."

Prosecutor Becky Mangold asked, "Did the RNC consider replacing Mr. Trump as a candidate?"

Westerhout told the jury, "It's my recollection there were conversations how it would be possible to replace him as the candidate if it came to that."

Westerhout testified that after Trump won the election, she helped with the presidential transition.

She said she earned the nickname "Greeter Girl" in the media after she helped coordinate meetings at Trump Tower, appearing in videos and photos accompanying potential Trump appointees in the Trump Tower lobby.

Prosecutors have called their next big witness: Madeleine Westerhout, who was Trump's director of Oval Office operations in the White House.

Westerhout was subpoenaed to testify.

Asked if she is nervous to testify, she responded, "I am now." This is her first time in a courtroom, she said.

Trump leaned forward in her chair, watching her intently.

Former President Trump, on his way out of the courtroom at the end of the day's proceedings, assailed Judge Juan Merchan for declining to gag upcoming witness Michael Cohen for remarks he's been making about Trump and the case on social media.

"There is no gag order to Michael Cohen. What the judge did was amazing, actually was amazing," Trump said of Merchan telling prosecutors to ask Cohen to stop making comments.

"Everybody can say whatever they want. They can say whatever they want. I'm not allowed to say anything about anybody," Trump said.

Trump also reiterated that his repayments to Cohen for Stormy Daniels' hush payment were properly recorded in his company's ledger. Prosecutors have said the repayments were unlawfully marked as a "legal expense" to conceal their true nature.

"I didn't do the bookkeeping. I didn't even know about it, but a very good bookkeeper marked a legal expense down as a legal expense," Trump said. "They didn't call it construction. They didn't call it building something or concrete or electrical cost. They called it, very simply, a legal expense to a lawyer -- who's a lawyer, not a fixer -- he's a lawyer."

"A legal expense to a lawyer," Trump repeated.

-ABC News' Kelsey Walsh and Mike Pappano