The phrase "to lead the line" means to be the main attacker or striker in a soccer (football) team. It refers to the player who is positioned up front, closest to the opposing goalkeeper, and whose primary responsibility is to score goals by receiving passes from their teammates and attempting shots on target. The term "to lead the line" implies that this player has been given a crucial role in attack, and it's their job to create chances for themselves and their teammates, as well as provide a physical presence in the opposing team's penalty area.