I personally would have a 'very open' AKA 'Fill In The Blanks' TEMPLATE available on standby should anyone request it:
I '
Your Details' Promise to do '
Job Description' for '
Their Details' to be completed by '
Comp Date' and payment will be made on '
Dates of payment' etc etc...
Then it's there and available should you or the other party wish to use it - But it all depends upon the 'size' of the company / person hiring you... Someone wanting a job worth a few hundred bucks may not wish to bother with paperwork...
However had I been hiring you (back in my heyday that is) you would have been signing contracts prepared by me. Not the other way around
So have it to hand if needed, but bigger jobs will probably have their own contracts for you to sign
