Not sure if this has been submitted, but this is literally how we make ice coffee at starbucks.
Brew your coffee at double strength. Meaning if you usually put in 2 scoops of grounds for your machine, do 4.
Once its done brewing, add ice directly to the hot coffee. Its best to put equal parts ice to coffee, but you don’t have to if you want it stronger/weaker. It was brewed at double strength so this won’t water it down. Mix it up!
As for sweetener and cream you can do whatever you like. You can go to your local starbucks and buy any syrup (except seasonal ones) or just use what you do normally. I advise against powdered sugar though - it won’t dissolve well. Some supermarkets have liquid sugar too, or the flavored creamers might be the cheapest option if you like both cream and sugar in your coffee.
I’ve seen some other methods but a lot of those take prep work or wait time - having to let it cool overnight or wait for coffee-ice cubes to freeze. This takes as long as it would take to brew coffee normally as long as you have ice cubes ready.