Wolf river Apple trees,best fertilizer.
I suggest you start out with a soil test to find out what the potassium and phosphorus needs are. If you have a rich soil, you may not need any fertilizer. Sandy soils generally need one or two applications per year.
Many Michigan soils have sufficient phosphorus. If that is the case for your site, choose a fertilizer that has lower amounts of the P component. On the fertilizer bag, the order is N-P-K (nitrogen, phosphorus, and potassium). So use one with less P. Examples: 15-5-10. 20-0-6. There are many formulations. Avoid using one with weed killer under the tree. Apple trees are less fussy about the type of nitrogen in the fertilizer. Urea, ammonium nitrate, calcium nitrate as the nitrogen source.
See the following link for pruning information:
A more advanced discussion with pictures can be found here:
The proper pruning method depends on the current condition of your trees, the tree health, rootstock, age, etc. If you reply with pictures we can give you more specific recommendations.