The Civil Partnerships, Marriages and Deaths (Registration Etc.) Act received Royal Assent on 26 March 2019, and extended eligibility for forming a civil partnership to opposite sex couples. The first opposite sex civil partnerships took place on 31 December 2019.
You can read more on the difference between a marriage and a civil partnership by going to Gov UK website.
A civil partnership does not require a ceremony therefore you can choose to sign the schedule in front of two qualified witnesses by booking a statutory ceremony appointment (subject to availability). If you wish to combine the signing with a full ceremony then you will need to book a venue and registrars ahead of booking an appointment to give your legal notice of intention.