Simply speaking, a contract is a legally binding agreement between two parties. It can outline the terms and conditions under which each party will operate during the period in which they work together. It would be a good idea to run any contract you draw up or receive by a legal practitioner to understand all conditions and liabilities.
For example…
If you were impressed with your daughter’s boyfriend’s graphic design skills and wanted him to spruce up your website, it would be a good idea to draw up a contract of the services you expect of him, the fee and any other conditions of the agreement. After all, you wouldn’t want him to demand a share of your company just because you didn’t lay out the rules, would you?