In order to ride a Horse, all you need is a Saddle. Unfortunately, you cannot make a saddle, you have to find one. You can find them occasionally in chests around the world. Optionally, you can put Horse Armor on Horses (not Donkey’s or Mules).
In Minecraft, a saddle is an item that you can not make with a crafting table or furnace. Instead, you need to find and gather this item in the game. Most commonly, a saddle can be found inside a chest in a dungeon or Nether Fortress or you can catch a saddle while fishing.
To craft a saddle five pieces of leather and two sticks are needed. To start, in the crafting table put a piece of leather in each corner. Then put the fifth piece of leather in the center of the middle column. After that put a stick in each of the remaining spaces in the middle column.
Feeding a horse will make it easier to tame. They will eat wheat, hay bales, sugar, apples, bread, golden carrots, and golden apples. Mules are not found naturally in Minecraft.
Add Items to make Leather Horse Armor
In the crafting menu, you should see a crafting area that is made up of a 3×3 crafting grid. To make leather horse armor, place 7 leather in the 3×3 crafting grid. When making leather horse armor, it is important that the leather is placed in the exact pattern as the image below.
Elastic on one end of your girth may cause the saddle to slip sideways, especially on broad horses, try turning the girth around or replacing with a girth with elastic both ends or no elastic.
There is no one answer but on average I would say 60 days. I have seen as little as one week, but usually the first 30 days to get the horse on board then add instructions the second 30 days.