You don’t have to have someone official to create and lead the funeral ceremony – unless you or the person who has died wants a religious funeral in which case you’ll need an authorised religious appointee. Consult the appropriate faith group.
Anyone can lead a funeral service. Reminder: a funeral has no legal status.
You can create your own funeral ceremony and lead it yourself if you want.
But if that’s going to be too much for you, your best bet is to find a good celebrant.
People who conduct non-religious, semi-religious and spiritual funerals are all called celebrants. It’s not a great word but there doesn’t seem to be a better one.
A semi-religious funeral is one that may have a hymn or two and a prayer in it, but the service is not led by a religious minister.
Most celebrants conduct both non-religious and semi-religious funerals.
Humanist celebrants only conduct non-religious funerals and say they’ll say no to the inclusion of any act of worship.—like a hymn or a prayer. If you want to sing a hymn for what they call cultural reasons – eg, Abide With Me because of its FA Cup Final association – they’ll be happy with that. The same goes for a poem with religious references.
If you want a funeral which expresses spirituality, find an Interfaith minister or a celebrant that states they help families to create a spiritual funeral..