The 'Total In Your Party' field is required as it will determine the number of fields that are displayed on the next step for your guests to enter in their names and details.
You can, however, remove this question in one of two ways:
1. Set the max number in a single party to 1. At 1, the system will know there can't be more than 1 person in a party (if this is applicable to your event), so will no longer need or display this field.
2. Use a guest list. If you pre-enter the names of your guests, the system will already know who is in each party, so will just ask for first and last name.
The text of this field can also be customized by going to Setup > Advanced > Language.
Tags: total in party, party number, drop down, number in party