Family visa for wife and stepchild under 18

[Gunay]

Good afternoon.
I am a citizen of Azerbaijan Republic and recently got married to the british citizen. I also have an 8 years old child from the previous marriage. Me and her father share custody over the child. He agreed to give a permission for child's permanent living in the UK.
We are thinking to apply for family visa now, but I am not sure what kind of visa we should apply for in case of my child.
I would highly appreciate any recommendations.

Thank you.

[vinny]

Difficult to succeed without you having sole responsibility or there are other serious and compelling reasons.

[Gunay]

Thank you.
But lets say I have a permission from child's father to take her abroad for permanent living. In that case what kind of visa I should apply for for her?