The pick line in soccer betting refers to a type of bet.
When a game is listed as a pick, the goal line spread does not come into play. In order to win your bet, you just need to have your team win the game. If they win, you will win your bet and if they lose, you will lose your bet.
A pick spread basically means that the two teams are fairly even, and the bookmakers expect the game to be close.
An example of a pick bet came in the 2019 UEFA Champions League round of 16 tie pitting Tottenham against Borussia Dortmund. The odds for both teams to advance were the same, at -110, so when the odds came out, both could also be class as a pick bet. Both teams had the same chance to advance, so you got good odds either way.
But with the good odds comes more risk. Since the teams classed as a pick, it is basically a toss up. If the match was played 10 times, the oddsmakers would expect that the outcome would be pretty close to 50/50.
Tottenham ended up winning the tie 4-0, so a $110 (or pound, or euro) bet on the Hotspurs would have returned $100.