Married Filed Jointly for TY2024; owed much more than we expected

For TY 2024, my wife and I filed jointly. We both work full-time, and we ended up owing much more than we expected, nearly $2600. We asked for a call-back at the end of our filing and the person we spoke with said that my wife's withholding was only around 10% when it should have been greater than 20%. She has looked at her current W-4 information on her employer's Workday system, and we have a few questions:

1. Her current info has "Number of Allowances" set to 1. Should this be a different value?

2. What does "Allowances" mean? Is it the same as Deductions or something different?

3. How should we fill out the "multiple jobs or spouse works" field?

 

Thank you!