A court of protection order is a legal document from the court appointing someone else (a deputy) to make decisions for someone who has lost their mental capacity. The court decides who to give responsibility to, and will supervise the deputies to make sure the account holder's interests are handled correctly.
In Scotland you would apply for a guardianship order, and in Northern Ireland it is a controllership. There may be slightly different procedures relating to these documents, and so you should speak to the relevant office in your jurisdiction if you aren't sure about anything.
The court you apply to depends on where you live:
In England and Wales, or Scotland, you may be given an interim or emergency court order to help with what’s known as a one-off decision in England and Wales, or an intervention order in Scotland.