There are basically two ways to reduce the number of asylum applicants in the U.S: speed up official decision making, and reduce the number of persons who can stay around and apply for asylum. One measure for the second option is expedited removal. Trump greatly expanded use of this provision, and Biden did further, in part by adding power to personnel at the border that further cut off access to the courts.
The expedited removal of persons just entering the U.S. and within 100 miles of the border authority, created in 1996, was expanded in application by Trump in 2019 and by Biden several times. It is at the core of efforts to cut off the flow of asylum cases going to immigration courts. Go here for an description of the provision, which in its original language was quite expansive but relatively underused until Trump.
In 2017, one quarter of persons apprehended by Customs and Border Patrol, or about 100,000 were returned (basically to Mexico) by expedited removal. Given there were about 1.5 apprehensions in FY 2022 (unduplicated count), hundreds of thousands might have been ejected that way.
In July, 2021, the Biden administration sought to expand “expedited removal” processing at the Mexican border. This rule was implemented in May, 2022
In March 2022, the administration proposed a rule (which was stalled due to legal challenges) to assign asylum cases directly to asylum officers, employed by USCIS within the State Department, to make full decisions on applicants, and to make other removal decisions previously assigned only to immigration courts, within Homeland Security.