This claim is misleading. The Trump administration has long emphasized an "America First" approach that it said would bring back manufacturing jobs. While there was an uptick in factory activity in 2017, it was short-lived.
US manufacturing has been in a technical recession since mid-2019. The sector has declined largely because of a broader slowdown across the globe and tit-for-tat tariff fights that drove up prices and disrupted supply chains.
Trump was correct that 12,000 new factories have been built during his term, but Bureau of Labor Statistics data shows the vast majority of those consist of five or fewer people. In December, about 12,000 factory jobs were lost.