A very simple Form option
For different reasons, you may want to remove the first name field altogether. Here's how:
1. Click on the first name field and make sure it's not required (uncheck the 'Required' box).
2. Select Delete Field (just below 'Required' to remove the field from your Form.
For Legacy Forms (pre July 2018)
Add one line of CSS to your Form. Just drop in one line of CSS and you can hide the first name field from your visitors:
.ck_first_name_field_group {display:none;}
NOTE: if you want to hide it for the 'naked' Form style, the css will be:
.ck_first_name {display:none;}
That code can go under the style settings for each Form. Or, if you wanted it to apply to every Form on your entire site you could add it to your main site stylesheet!