This past March she helped facilitate a meeting at the White House with Vice President Mike Pence for 100 Hispanic pastors and denominational leaders, said Tony Suarez, the executive vice president of the National Hispanic Christian Leaders Conference, a network of 40,000 Hispanic evangelical congregations.

Ms. White led a pentecostal-leaning church, recently renamed City of Destiny, with thousands of members near Orlando, Fla. She stepped down as senior pastor in May and announced plans to start a university and 3,000 new churches. In 2007, Senator Charles E. Grassley, Republican of Iowa, and the Senate Finance Committee had investigated her ministry’s tax-exempt status, but the investigation was eventually dropped.

Ms. White first met Mr. Trump in 2002, when he called her after seeing her preach on a Christian televangelist program. They stayed in touch, she bought an apartment in his 502 Park Avenue building, and he reportedly attended Bible studies she occasionally led in New York.

He invited her to attend the first season finale of his show “The Apprentice,” where she prayed with the cast and crew before the live taping.

She prayed with him before he went onstage to accept the Republican nomination for president in Cleveland. She became the first clergywoman to lead an inaugural prayer when he took the oath of office, according to Mr. Trump’s inauguration committee.

Her employment at the White House raises questions about whether she may be putting her church’s tax-exempt status in question, as churches are not allowed to engage in overt political activity. Though she has stepped down as the pastor, she could run into difficulty with the Internal Revenue Service if she remained active in the church, even in an informal role, while working for the president.

“My sense is if she is leaving her church position and making a clean break that there would be no I.R.S. problem,” said Fred Wertheimer, president of Democracy 21, a campaign finance watchdog. But, he added, “If she is continuing in an official public role for the church while working in the White House that would cause a tax status problem as she would be using the church for political purposes.”