This important and often large legal document protects the resident and rest home / hospital by setting out the responsibilities of both. Care Providers are required to provide an Admission Agreement. Ask to take the agreement away with you and study it carefully. If there is anything you are not clear about, seek advice.
If you are not happy with the terms, try to negotiate a different arrangement and change the agreement to reflect this. You initial changes just as you would any other legal document. For example, you might negotiate a reduced period of notice - two weeks is often considered a reasonable time frame for both parties. There is no charge for preparing or providing an Admission Agreement.

What should an admission agreement include?
This is covered in the Age Related Residential Care Services contract, section D13. View the full contract:
 

Age Related Residential Care Services Contract

The Admission Agreement should specify any extra charges. By signing it you undertake to pay these costs if you use the services listed. Some facilities may ask you to supply a guarantor for payment.
Your Care Provider cannot charge you for any services you receive that are already part of its contract with the District Health Board. These are known as Contracted Care Services. Services generally include GP visits, medications and incontinence products.
There should be no extra costs for any resident, unless these  have been agreed to in the Admission Agreement. Residents have the right to decide at any time to receive or stop receiving any additional service.
For more details on Contracted Care Services follow the link (above) to the national contract.
The Admission Agreement is required to cover issues such as liability for damage or loss of residents’ personal belongings, staffing, resident safety and security, transport policies, procedures, costs, complaint processes and information on when a resident may be required to leave a facility.