Uniform and shoes and trainers.
Pencil case and calculator. We were also asked for a protractor and compass. The school I work at ask for blue, black, green and purple pens 
Bag to put it all in.
Lunch box? And water bottle.
We have been asked to buy a French dictionary, and an apron for food - that came as a request around Christmas.
We were also asked to donate about £10 for food and DT materials.
Some sort of device to access apps - all our homework is put on an app, that DS needs to access to find out what to do. Some of it is then done on the tablet. Some is done on paper.
We started DS walking home alone on nights where he or his brother had an afterschool club - ie I wasnt already at school. I also started it by telling him I was meeting X just before school collection, and if I was late, he should just start walking g, and I'd meet him half way. How will you daughter get to secondary? Walk or bus? Start using busses now if that's the way she will be travelling.
I think Covid has shrunk the current Y6 world quite a lot, and many will he anxious about travelling g to and from school.
My son is totally disorganised. All his school books come home (not all schools do this). So we have a plastic box with a lid. I've photocopied his time table several times. One is hidden so I can always access it, and one is stuck ontop of the box that all his books live in. If I find a book somewhere in the house, I tell him where it is, and that it needs putting away properly. To date, weve only lost 1 water bottle (compared to primary, this is awesome progress!).
I also bought some keyrings made from a plastic spring. His house key and bus pass are attached to his school bag, and are NEVER removed - the keyring is long enough to open the front door without detaching it from his bag. Key and pass get tucked in the front pocket of his bag when not in use.
Good luck. They do a lot of growing up in the next 6 months.