Your pipe's start form is it's front door. It represents the input of your process and it's extremely important that you take your time to structure it properly to make sure you ask for all the information you need in it without adding unnecessary fields.
Let's assume your creating a new process from scratch. Your form will come with a single short text field asking 'what?'. To make your form more complete you'll need to add more fields to it, here's how you do it.
How to add fields to the start form
To add a new field to the form we'll start by opening the form by clicking on the "+" icon in the lower right corner of the screen.
Then, we'll click on "click here to customize this form" to select the type of field we want to add. Once the field window is open we'll add the field label (its title) and we can also add a description and help text, its options (if it's a multiple choice field), establish if it's mandatory and editable in other phases.
Once you're done editing, save it and that's it, your field is created!
Keep on going until you feel like your form is complete and you're asking for all the information you need to kick off your process!