The crafting recipe for the golden apple got removed from the game unfortunately. Unless you are playing on an old version of the game, the solution in the spoiler does not work anymore.
*** Spoiler - click to reveal ***Very easy, you need to make a notch apple. For that you need 8 golden blocks and 1 regular apple. Then go to a crafting table and place the apple in the middle, surrounded by gold bricks (if using the original crafting) or simply click on the golden apple to create one (if using the PE crafting).
Your best bet would be to use an achievement world. If you don't feel like doing that you will need to find one in a chest, located in a woodland mansion, nether fortress, desert temple, etc. I've posted the possible spawn percentages, copied from the Minecraft wiki here below:
Enchanted golden apples can be found in 3.1% of dungeon chests, 2.6% of desert temple chests, 1.4% of chest minecarts in abandoned mineshafts, and 3.1% of woodland mansion chests, all in stacks of 1. In Bedrock Edition, they can be found in 3.1% of woodland mansion chests in stacks of 1. Source:
https://minecraft.gamepedia.com/Golden_AppleLuckily for you, I've decided to post achievement worlds again for this update. If you're unsure how to get the worlds onto your PC/android/ios device, the following forum I started might help, otherwise there are plenty of youtube videos.
Achievement worldsYou can download the Notch apple world from here:
https://www.dropbox.com/sh/v6ggssr1ag7uerp/AACU3QfRen68hOMno...Once in the world, open crafting table, craft notch apple. Eat notch apple. Bleep bloop