There are a few companies in the US that work with European and other foreign clubs. Most of these seem to follow a similar model. Players who sign up train and play games over a two to three day period in front of staff, coaches and scouts. In some instances, especially since COVID, the combine staff members have been granted the authority to make selections on behalf of foreign teams.
Several of these soccer combines select the top players from their event and invite them to a showcase event abroad. Most of these are structured in similar ways. The selected players travel and stay in select European venues. They train with local clubs and have opportunities to play with professional and semi-professional teams. If they impress, they may be offered a position on a squad.