She also met with a number of the displaced children, and signed a poster welcoming her to the facility.
Melania Trump later visited the Upbring New Hope Children's Center, where she spoke with children and staff.
No clear plan has yet been proposed by the government to reunite the parents and children who have been separated.
That was before Trump signed an executive order halting the practice of separating children form their parents who cross the border illegally. She is aware of the message she is sending, which is typically one of aspirational luxury.
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She visited three classrooms, each time asking the children where they came from, their ages, how long they'd been at the center and their favorite subjects. "It's a basic rule of thumb that if you don't want to make your clothing the focus of the story, then choose what you wear carefully so that it's not", she said.
President Donald Trump first announced the trip by his wife, who was touring a non-profit social services center for migrant children, before heading to a customs and border patrol processing center, according to a statement from her office.
On Wednesday, Trump made a rare retreat, signing an executive order that he said would end family separations as Congress prepared to consider legislation that would force a halt to the policy. The children at the center stay for about 58 days, with half of the children being placed with their parent, 40 percent placed with a relative in the USA and about 10 percent going into foster care or to family friends.
When HuffPost asked Trump publicist Stephanie Grisham of the outfit, Grisham said: "I'd hope you guys would want to cover her visit with children today".
"These children as they are being separated by their parents are going to face the traumas that are part of post-traumatic stress disorder - anxiety, stress, depression, nervousness", psychologist Dr. Jeff Gardere told Inside Edition.
Fashion is political for the first lady.
She had changed into more sensible sneakers by the time she got off the plane in Texas but the Twitterverse had a field day sneering. She called on Congress to work together on immigration legislation that would benefit the children.