How best to repaint wrought iron patio set?

Joyce....I would sand and remove any peeling paint then clean and spray with paint.

Use sand paper or a wire brush to remove any rust or loose paint, clean it well and let it dry-best done on a windless day.

Then spray with a product like Rustoleum, found at big box stores like Walmart and DIY stores.

https://www.youtube.com/watch?v=obl9eml60V0

As said, wire brush or sand all rust and loose paint. I've found that using Rustoleum primer for metal is a better choice for the base rather than paint and primer in one. Once dry, paint with the color of your choice but be certain to use only paint meant for metal!

Use sandpaper to remove any chipping paint and then spray paint