The idea is to avoid (or reduce) Inheritance Tax when the property owner dies. However it's worth remembering that there's no Inheritance Tax to pay anyway if the value of the deceased person's estate is less than £325,000. (If they were pre-deceased by a spouse or civil partner, who left everything to them, they get their spouse's allowance as well, meaning that there's no Inheritance Tax to pay unless the value of the estate exceeds £650,000). So for many people there's probably no point in putting their property into a trust anyway. (Some schemes involving trusts claim to be able to help people avoid the need to use their home to pay care home fees in the event of them requiring such care but many financial advisers have doubts about the validity of such schemes).
You should note that you no longer own a property after you've put it into a trust. It's the trustee (who administers the trust) who then owns it. So if you allow a firm to become the trustee you could be in big trouble if that firm later goes bust, as the house you live in will be counted as part of the firm's assets and could be sold to pay off its creditors. See here:
https://www.bbc.co.uk/news/uk-england-suffolk-45829270
This page, from the independent (Government-funded) Money Advice Service, explains more about trusts:
https://www.moneyadviceservice.org.uk/en/articles/using-a-trust-to-cut-your-inheritance-tax