Create a Magic System

I think you will need to be more specific if people are going to reply to this. I mean, to start with, "when" and "where" this system is operating is very important to the answers. Then I'd ask you:

1. Are you looking for a pseduo-scientific explanation that doesn't break the Laws of Thermodynamics, but explains where the additional energy is appearing from?
2. Are you looking to create some rules of useage - why some people can use it, why some cannot, where it can and cannot be used?
3. Are you looking for help with the names of spells?

There is also a suggestion of a certain amount of "Do your own homework!" in the asking!

I don't think the first question is very important. It's Fantasy. I can accept that, “there are more things in Heaven and Earth, Horatio, than are dreamt of in your philosophy,” and leave it at that. I didn't need any "midi-chorians" to explain The Force in Star Wars. I do however, like a little bit of telekenesis myself.

The second and third questions are really where you can have some fun and you don't need someone to do that for you. Read books on "real" historical Magic use and beliefs. If you want to be original you will have to look very hard, but read about ancient customs and beliefs from old civilisations around the world. You'll need to heavily adapt them to prevent accusations of "cultural appropriation" but definitely try to avoid having someone in a cloak or pointed hat with a wand, saying latin names, read from a large book. If you do, then it really needs to have a different spin on it, such as in the Rivers of London, Peter Grant, police detective series.

Avoid anything that looks like Dungeons and Dragons. You should certainly avoid setting it in a school for Wizards or Witches. I'd personally avoid even using "spells" at all actually. Read some Stephen King books such as "Carrie" - magic or spells are not mentioned, she is just different (I think his attempt at an explanation for the phenomena is the weakest part of the story, but necessary for the plot.)

The thing about historical English Witches is that they were really just women of a certain age who refused to stay in their place, and to do what they were told by young men. They had some knowledge of herbal remedies and some folk medicine, passed down by word of mouth, and were probably respected by their communities for this knowledge. In a patriarchical society, that could never be allowed to continue.
For anyone like me who found the Sanderson link interesting, here's the latest lectures I could find (2020)
hi all can anyone help me create a magic system
We can help by asking you some questions:

What do you need it to do?

What limits do you need it to have?

Which people can use it? Elite only? Can the Working Class use it? Can it be industriality?
What is its cost to the world or to the practitioner?
What equipment does need and how is that equipment obtained?

Does its use attract problems? Entities want to sniff up spare incense fumes or pinch your supplies?
Are there astrological factories or geomantic factors that change its power?
Maybe it can backfire when certain astrology happens.