Not to send my child to reception year?

I really wouldn’t want my child to skip reception and jump straight into year 1. Reception is all about play, with some maths and phonics thrown in, but the learning the do, in terms of social skills and independence, is vital imo. The jump in terms of type of learning is quite big when they move to year one. I wouldnt want my child to miss out on reception and have year 1 as their first school experience

It used to be common for schools to have starters at January and after Easter (for the ones who have turned 5) but it then became the normal for everyone to start in September so everyone essentially was starting at 4.
Under the old system it meant some children had 2 terms of "Reception" (the Sept - December borns), the January - Easter borns got one term, and the summer borns started in the September when they would be going directly to Year 1.
So in theory the current system is fairer because everyone gets the full 3 terms....but it means starting at 4.
However....
Reception is very play based.
A lot of it is learning how to follow rules ("it's time for everyone to sit on the mat"), taking turns, learning independence (dressing for PE), learning how to make friends etc.
It's technically called "Foundation Stage" and that's what it is - setting the foundation for how school works.
But most of it is just play for the children....they don't realise they are learning half the time.

They don't really learn much in the traditional sense, mostly learning through play , PE, crafts, singing etc.
Both mine started in the September when they were 4 (January and April birthdays), the April birthday one settled in better even though they were younger so depends a lot on the child.
They both enjoyed it though and had lots of fun with their friends.
Better than being stuck at home imho, and anyway I worked so did DH so it's free childcare!

Reception is as others have said play based. I really don't know why you would want to skip it out.

Do people in general send their kids to reception at 4 or do they wait till 5? Or does it vary quite a bit?

yes, in general people send their children to school at the start of the academic year that will turn 5 in, so at the age of 4. Some people do wait, but it’s not the norm.

Reception is mostly play based, but the children are also learning how to sit still and various other social skills.

Would your child then start in year 1?

Reception is based on principles of free play and continuous provision. It’s an incredibly important year for children and I would strongly advise you don’t skip it.

I sent both of mine in the September (December and April birthdays) and am likely to do the same with my youngest, who is a July birthday so will only lately have turned four.

Reception class is quite play-based in our school.

It's incredibly unusual to wait until compulsory school age and your example of waiting til Y1 only works with a summer born. As a teacher, I'm pretty confident I could have taught what was needed over the Reception year but Reception was exponentially better than private nursery and, like most people, I have a job so there was no option of my child staying at home. My child describes Reception as 'just playing' and absolutely loved it. Genuinely never had a bad day. Do I think most people could teach the Reception content? Honestly, no. That is why schools employ trained teachers. It's probably less of an issue if you're going to home ed for primary, but otherwise I imagine it's a tough transition to Y1.