Matching the form to the job.
A CONTACT FORM
Three fields. Name, contact, message.
Do not ask for more.
A QUOTE REQUEST
Enough to give a meaningful answer, and no more.
Consider whether a conversation would be better than a long form.
A BOOKING FORM
Service, date, time, contact details.
If availability matters, use a booking system rather than a form.
A JOB APPLICATION
Contact details and a document upload.
Store uploads securely. CVs contain a great deal of personal data.
A SUPPORT REQUEST
What is wrong, what they have tried, how to reach them.
Asking the right questions here saves a round trip.
A NEWSLETTER SIGNUP
Email address. That is all.
Asking for a name reduces signups noticeably.
A SURVEY
Short. Completion falls sharply with length.
WHAT APPLIES TO ALL
Only ask what you will use.