Major League players with less than three seasons of service time (not including Super Two eligible players) are not eligible for arbitration and must accept whatever salary their team determines for them. This amount must be at or above a certain amount - in 2019 the league minimum salary is $555,000.
Just because the player is forced to accept that amount does not mean they necessarily agree to it, however. Sometimes players will not sign the contract and the team must renew the contract. This is done for symbolic reasons and does not have any real impact on the actual contract.