The easiest way to apply for a deed poll is via the “unenrolled” route. This will be accepted by the passport office, DVLA and most other organisations including the majority of banks and is free. You can either write one yourself or use any number of websites that offer this service such as Free Deed Poll to generate one for you. Once you have printed it out you must get two people to sign your deed poll as witnesses. To act as a witness the person must: be over 18 and live in the UK, have known you for a reasonable amount of time and have known you by your previous name. They will need to provide their full name, address, and occupation as well as their signature. They cannot be family members, your partner or anyone that lives with you. They must also have full mental capacity, this means that they must be able to make decisions for themselves without being affected by an impairment or disturbance of the mind (disability or illness). Everyone has full mental capacity by default unless proven otherwise. They must also be in your presence when you sign the deed poll. Apart from these conditions, your witness could be anyone — a friend, neighbour, or colleague, for example. Once this is all complete it is official (and yes, it is that simple!). It is recommended that you make a few copies of your deed poll as you will need them to change your name on all other documents.
Alternatively, visit the gov.uk website for more info.
Official forms can be found here.
A very good, non-governmental website shows what you need to do here:
This information is accurate as of August 2021.