I want to paint my kitchen cabinets white, I don’t know what is best

Since they are covered with poly, you will need to sand them completely to remove the old finish. Take down the doors, and remove the hinges and hardware. Be sure to label the doors so you know where they go. Sand each door thoroughly, then sand the frames of the cabinets and the drawer fronts as well. Begin with one coat of good primer...Kilz or Zinsser. Then, using a good quality Kitchen and Bath paint, paint two or three thin coats of paint on the cabinets, frames, drawer fronts, etc. Let dry completely between coats. Rehang the doors and replace all drawers. Add hardware. Enjoy your new kitchen!

I have done this and a good 24 to 48 hrs between coats is best if you are using an oil based paint. Michele advice is great

First of all DON'T use Latex paint! use oil base like rustoleum for much less chipping!

First wipe everything down with trisodium phosphate (TSP) to remove dirt and grease.

Fill any cracks chips etc and lightly sand with 200 sandpaper for a uniform surface. Pay special attention to edges and cracks to insure sanding everything.

Blow or brush everything off to remove all dust and brush a thin coat of paint after removing knobs, check overall to insure there're no runs or excess paint on the edges where they come together. leave doors and drawers open until the paint is pretty dry and open and close the doors to insure the hinges are not stuck.

Apply a second slightly thicker coat to cover

i would clean them with tps to get rid of the grease, lightly sand, tack cloth and then prime with stix before painting. It’s a lot of work but you will not be touching up your paint later on

Remove doors and hardware, lightly sand doors and cabinet facings. The fastest way to get through the door process (painting fronts and backs) is to screw in cup screws to the inside bottom lip of the door. When you do this you can use metal coat hangers to hang the doors to dry To speed the process up. We used two ladders with two metal rods or pipe (this gives a high and low rack) to hang the doors between coats of paint. Paint primer on one side in the morning (best to paint thin coats of paint), reverse side in the evening. Hang to dry. The best paint for cabinets is enamel paint, this will withstand wear and tear, and use won’t need to add a seal. If you painted your first coat in the morning you are good to go to apply the first coat of paint the following morning/reverse side evening, again use thin coats. Again 24 hours later apply final coat morning and evening. Let dry 24 hours and reattached hardware. We were able to paint the cabinet facings between morning and evening door work. We learned by hanging the doors we saved DAYS of extra drying time and work. Good luck😊

I understand if you use milk paint, you can skip some of these steps and it's far less complicated. Clean the cabinets well to remove all dust and grease. Just use a very light sand and then paint. Use a topcoat to protect the finish.