My daughter is 6, and me and my partner wants to adopt her. Her biological father, at 1 point played a big part,but for the last year and half, she has not seen him. My daughter, want's to call my partner daddy, and is always saying she loves him. I'm not sure where to even start? Any help would be much appreciated.

Ok, so I can assume partner is not a "same sex partner" which is another issue in many areas.

You did not say where you are at, but in the US, many states will require that partner to be a husband and married for about one year before they will allow for the adoption.

After that ( or in states that allow long term partnership relationships) you will file in court for adoption, and have the bio father sign over his rights to allow the adoption

I'm in uk.ive had a quick look online, but all reads like a mindfeild