Legal Requirements of a Contract.

Contract Terms
The legal requirements of a contract usually refer to the terms. If an illustrator has a contract to do some work for someone this is called a 'contract to provide services'. The contract is an agreement between the illustrator and the person they are doing the work for which sets out their conditions of employment/duration which services are being provided, their rights, responsibilities and their duties.

Agreements
All agreements must be made before work is started to ensure everybody knows what they want and how they want it without changing their mind. No changes can be made to the agreement once everyone agrees but either client or illustrator can ask each other if they can make changes and if the other person agrees, the changes can be made.

Written Statement

A written statement should include;

• The business’s/clients name 
• The illustrator's name
• Description of work
• Start date
• How much the illustrator will be paid and how often
• Deadlines
• End date of contract

Reference

https://www.gov.uk/employment-contracts-and-conditions

http://91.109.3.30/~theaoi/theaoi/members/contracts.html