Find one of the parts warehouses (
https://www.appliancepartspros.com/) is one I have used to look up parts.
Type in your appliance model number in the search box.
Look up the category (electrical / bearing / control board / etc)
Look for the exploded view if you are not sure what the part is.
Find the part number including any alternate part numbers
(Many brands and models share the same parts)
So it could be a Maytag H45S or a Kenmore YT87, but they are the same part and are interchangeable.
Check Amazon to see if they have either of those part numbers, if so, read the reviews, some are chinese junk.
Nice thing about Amazon is free returns, free shipping (if you have Prime), and have it in 1 to 2 days.
Decide if you want to buy on Amazon or buy from any of the Appliance Parts guys who sell online or try Ebay.
It honestly is a crap shoot unless you buy from the manufacturer directly.
Might get the same part from Amazon that you get from Appliance Part Pros.